Double Strike hits twice. Armor Ignore ignores a target's resistances.
Both special moves have 10% penalty to damage. In practice this means a negative 0.9 bonus to damage that may be compensated by positive bonuses from slayer/honor/eoo.
When you use a super slayer weapon you need 50% bonus from Honor or EOO to reach 300% damage cap:
100% (base) * 2 (super slayer) * 1.5 (honor/eoo) = 300%.
When you use a super slayer weapon and DS or AI you need 67% bonus from Honor or EOO to reach 300% damage cap:
100% (base) * 2 (super slayer) * 0.9 (DS/AI) * 1.67 (honor/eoo) = 300%
(I have tested this for AI but haven't tested this for DS because I need to know exact monster's resist for accurate test)
When you use DS there is a hit chance check for each swing. So you can hit with the first swing but miss with the second one. There is +15 hci bonus for the second swing.
I don't know is there are any chance for the second hit when you miss with the first one. I think that there is not.
There is a cap 95% on chance to hit.
In a situation when an attacker has 45 HCI/120 skill and a defender has 0 DCI (a typical monster) a monster must have less then 98 skill to reach the cap 95% on the second swing. If the monster is under HLD effect (-25 DCI) it must have less then 138 skill to reach the cap.
A standard Bushido Paladin has 30% HLD, 45 HCI and 120 Swordsmanship.
When you have 30% HLD usually you reach the chance to hit cap. 8 seconds is enough time because you have 51% to re-apply HLD with two hits.
It doesn't matter for comparison but to get absolute damage values let's count our elf (no JOAT LJ) character has 120 Tactics/Anatomy, 150 STR and reached 300% damage cap.
Min-max (average) damage with AI (Bladed Staff) is: 165-201 (183)
Damage with DS (Double Axe) depends on monster's lowest resist (thanks to Consecrate Weapon). Here is a small table:
20: 276-332 (304)
40: 207-249 (228)
52: 166-199 (182,5)
60: 138-166 (152)
80: 69-83 (76)
90: 34.5-41.5 (38)
So you'd better use AI when a monster has 53+ in all resists. To find such monsters I suggest to use UO Stratic Monster Database.
http://uo.stratics.com/database/search.php?db_content=hunters
But you should keep in your mind that the database is not full. It usually doesn't contain data for new monsters that can't be explored with Animal Lore (Exodus monsters, human-like monsters, etc). Sometimes data contains min and max resists but doesn't contains average resists (for example, for Unbound Energy Vortex).
Also there are some monsters that can't be disco'ed.
I don't count Ortanord that seems can't be damaged by a weapon.
1) (solo) 53+ in all res (29 found):
http://uo.stratics.com/database/sea...=&AvgPois=&AvgMag=&AvgEval=&AvgMed=&Sort=Name
2) (with a bard) 67+ in all res (4 found):
http://uo.stratics.com/database/sea...=&AvgPois=&AvgMag=&AvgEval=&AvgMed=&Sort=Name
Corgul the Soulbinder
Osiredon the Scalis Enforcer
Slasher of Veils
Stygian Dragon
3) (with a necro) 68+ fire/poison 53+ in the rest res (6 found):
http://uo.stratics.com/database/sea...=&AvgPois=&AvgMag=&AvgEval=&AvgMed=&Sort=Name
The same as above plus The Harrower (both).
4) (with a necro/bard) 82+ fire/poison 67+ in the rest res (0 found)
I don't know resists for:
Cora the Sorceress
The Exodus Encounter (can't be disco'ed)
Travesty (can mimic your disco/necro and use it against you)
Invasion masters (can't be disco'ed)
Here is monsters with 133+ average wrestling:
http://uo.stratics.com/database/sea...=&AvgPois=&AvgMag=&AvgEval=&AvgMed=&Sort=Name
Both special moves have 10% penalty to damage. In practice this means a negative 0.9 bonus to damage that may be compensated by positive bonuses from slayer/honor/eoo.
When you use a super slayer weapon you need 50% bonus from Honor or EOO to reach 300% damage cap:
100% (base) * 2 (super slayer) * 1.5 (honor/eoo) = 300%.
When you use a super slayer weapon and DS or AI you need 67% bonus from Honor or EOO to reach 300% damage cap:
100% (base) * 2 (super slayer) * 0.9 (DS/AI) * 1.67 (honor/eoo) = 300%
(I have tested this for AI but haven't tested this for DS because I need to know exact monster's resist for accurate test)
When you use DS there is a hit chance check for each swing. So you can hit with the first swing but miss with the second one. There is +15 hci bonus for the second swing.
I don't know is there are any chance for the second hit when you miss with the first one. I think that there is not.
There is a cap 95% on chance to hit.
In a situation when an attacker has 45 HCI/120 skill and a defender has 0 DCI (a typical monster) a monster must have less then 98 skill to reach the cap 95% on the second swing. If the monster is under HLD effect (-25 DCI) it must have less then 138 skill to reach the cap.
A standard Bushido Paladin has 30% HLD, 45 HCI and 120 Swordsmanship.
When you have 30% HLD usually you reach the chance to hit cap. 8 seconds is enough time because you have 51% to re-apply HLD with two hits.
It doesn't matter for comparison but to get absolute damage values let's count our elf (no JOAT LJ) character has 120 Tactics/Anatomy, 150 STR and reached 300% damage cap.
Min-max (average) damage with AI (Bladed Staff) is: 165-201 (183)
Damage with DS (Double Axe) depends on monster's lowest resist (thanks to Consecrate Weapon). Here is a small table:
20: 276-332 (304)
40: 207-249 (228)
52: 166-199 (182,5)
60: 138-166 (152)
80: 69-83 (76)
90: 34.5-41.5 (38)
So you'd better use AI when a monster has 53+ in all resists. To find such monsters I suggest to use UO Stratic Monster Database.
http://uo.stratics.com/database/search.php?db_content=hunters
But you should keep in your mind that the database is not full. It usually doesn't contain data for new monsters that can't be explored with Animal Lore (Exodus monsters, human-like monsters, etc). Sometimes data contains min and max resists but doesn't contains average resists (for example, for Unbound Energy Vortex).
Also there are some monsters that can't be disco'ed.
I don't count Ortanord that seems can't be damaged by a weapon.
1) (solo) 53+ in all res (29 found):
http://uo.stratics.com/database/sea...=&AvgPois=&AvgMag=&AvgEval=&AvgMed=&Sort=Name
2) (with a bard) 67+ in all res (4 found):
http://uo.stratics.com/database/sea...=&AvgPois=&AvgMag=&AvgEval=&AvgMed=&Sort=Name
Corgul the Soulbinder
Osiredon the Scalis Enforcer
Slasher of Veils
Stygian Dragon
3) (with a necro) 68+ fire/poison 53+ in the rest res (6 found):
http://uo.stratics.com/database/sea...=&AvgPois=&AvgMag=&AvgEval=&AvgMed=&Sort=Name
The same as above plus The Harrower (both).
4) (with a necro/bard) 82+ fire/poison 67+ in the rest res (0 found)
I don't know resists for:
Cora the Sorceress
The Exodus Encounter (can't be disco'ed)
Travesty (can mimic your disco/necro and use it against you)
Invasion masters (can't be disco'ed)
Here is monsters with 133+ average wrestling:
http://uo.stratics.com/database/sea...=&AvgPois=&AvgMag=&AvgEval=&AvgMed=&Sort=Name