I though I'd throw up some links and info before books are blown on the wrong skill Laughing
List of worthless OE skills
* Dual Sword Mastery +1 Swiftness - Adds 8 Attack speed.
* Brave Heart +1 - Adds 10 CP.
* Fast Casting +1 - Adds 1 cast speed.
* Benediction +1 Bravery - Adds 16 CP.
* Master of Combat +1*Any Weapon Type* - Adds 1 PATK.
* Duelist Spirit +PvP Power - Adds 150 PvP Patk at +1, +10-15 pvp patk every enchant after. This is like critical power but is only affected by the +10% pvp bonus of the skill and 5% of the weapon SA if Ag or better. Doesnt get boosted by SS or PATK boosting buffs (pvp patk only).
* Duelist Spirit +Swiftness - Adds +5 atkspd at +1 and then 0.9-1.3 atkspd every + thereafter.
* Boost Attack speed +1 add 0 att speed, +2 add 1 att speed
* Fast HP Recovery +Power - Adds 0.5 hp regen, then 0.1 every +1 thereafter.
* Warrior Heavy Armor Mastery +Life - Adds +3.0 HP regen, then 0.2-0.3 hp every +1 thereafter. **
* Final Frenzy +Power - Adds +8 patk at +1, and +1 patk every + thereafter.
This list is taken from http://www.l2guru.com/forum/showthread.php?t=104583
please read it
Then, the major factor of OE is that the skill lvl changes. A skill learned at 74 is lvl 74 skill, although when enchanted the skill increases in lvl. For more and accurate info read: http://www.l2guru.com/forum/showthread.php?t=111589
here's also a link on how this translates to skill effectiveness against a lvl X target http://www.l2guru.com/forum/showthread.php?t=119600
Now for the main eventhttp://l2p.l2wh.com/skillenchant.html
chances and details of what the OE in question gives. This part is not complete, missing alot of info, there should be more?