The knight Watch ( eq classic Sk specific website )
http://web.archive.org/web/200009041...pell_three.htm
Delivers lifetap via touch, can be used with weapon. Adds a proc to your melee that drains (Level/2)+1 hit points (12-26 hp)
This is from September 4, 2000. Notice how it says max drain is 26 hp... that would mean this info was listed prior to the kunark expansion and not updated when kunark came out. 50/2 + 1 = 26 which should lead us to the logical conclusion that this is the way the spell worked in pre-kunark EQ.