Pirates 1 slot to 2 slots are 150% If you pull the pet right at 100% hide invis whatever and train it to 2 slot you can get another 50%. 2 slot to 3 slot 100% if you pull the pet at 100% when it hits 3 slot you can put it back on for another 25% if you did the 150% on the first pirate. 3 slot to 4 slot 50% if you will actually go to 75% because of the previous 25% left over from the second pirate. Which will save you 1 pirate in the 4-5 slot training at 25% per pirate. If you have the ship, the heavy cannons, heavy charges, and fuse cords and the skill with using the ship to scuttle the pirate ship fast and without taking much damage to your boat pirates are the fastest and best way to train pets. If not then the crazy mage is your best bet and still reasonably fast. I have trained 20 pets on 8 pirates from 1 slot to 5 slot.
Pirate Tips
NEVER train a pet that will disarm the pirate. Once disarmed the pirate will kill every pet fast, the have like 5000 wrestling and 5000 parry and use lots of spec moves.
Never let the pirates bow break see above

same applies as disarming. You can beat them down to their underwear but don't break the bow.
Learn to use your boat and not get damaged.
Hiding is a real bonus