I played UO from the day it went public to about 8 months after Trammel went live.
I am still struggling with some of the Item Changes, let alone some of the game changes.
Things that are not so apprent.
LRC=Lower Reagent Cost. This is a percent value from 0 to 100+ (>100 is a waste). It governs the chance that you will or will not actually use reagents. Such that at 100% you will not use reagents and do not need to carry them.
Mage Weapon -N. Where N can be any number from 0 to .... what ever. When this is on an item, it means that the Magery Skill will be used as the Weapon Skill, minus the N value. Such that 0 means no deduction from the Magery Skill. This in turn has a defensive computation that is akin to a passive Block of an attack. Others can give a more detailed explanation of the formula but it is basically your mage skill compared to the opponents weapon skill (mob would be wrestling) to decide if you were hit or not.
DCI=Defensive Chance Increase. This is caped at 45%. It is, in simple terms, attack avoidance/mitigation. Roughly means, at cap, you would have a 45% chance to avoid being hit. Stacks with Weapon Block.
Resistance %. Caps are at 70%. This means you would take the damage and reduce it by the percentage as the final damage amount. Simply put, it is damage avoidance/mitigation.
Slayer weapons. Slayer Types are MoB groups. When applied to the correct Group you do double damage. When applied to the opposite group, the damage done to you is doubled. When applied to a group outside the correct or opposing group, the weapon acts as normal. When on a Barding Instrument, vs the correct Group, you will increase your chance to successfully bard the mob by 15%. Versus the opposing group, you reduce your chance to bard the mob by 15%. Versus any mob that is not in either group the instrument acts as a normal weapon. On this note, an exceptional (player made) barding instrument gives a 10% increased chance to bard the mob. On Spell Books, your spells do additional damage when cast on the correct group.
And thanks T_Amon I had never seen that page. It was helpful.
You might also want to consider creating characters on TC1. Use the Give, set Commands etc. This will enable you to get most of the Artifacts, that can demonstrate the value of the components. You also get premade-complete sets of things, as well as enough resources to make items.
Using the resources and the set command you can experiment around to find out what the best template is for you and what things make that template work the best. I did this for 2+ Weeks to get my feet on the ground, while scouting all the shards to determine the one I wanted to select to be my shard.