ぽろり

removing 3rd job (quest related or not) npc will remove 3rd job in the game without actually removing it from the system.

changing 

max_preserve = 4 * pc->checkskill(sd, WL_FREEZE_SP) + (status_get_int(&sd->bl) + sd->status.base_level) / 10;

to 

 max_preserve = 2;

is a way that works for me, although you have to configure every "PreservePoints" in spellbook_db.txt to 1 since each of the skills have their own preserve points

14,1,6190         // limits cold bolt to 2 reads and 2 release.

so you wanna read 2 spell books then release it 2x? 

src/map/skill.h

#define MAX_SKILL_SPELLBOOK_DB 17

and you have to configure preserve points in db/spellbook_db.txt

str = (int)(rstr + (float)dex/5 + (float)st->luk/3 + (float)((TBL_PC*)bl)->status.base_level/4);

this statement carries the formula adding atk for stats str/dex/luk

rstr =  actual str the user has meaning 1 str = 1bAtk

dex = dex/5 per bAtk

st->luk/3 = luk divided by 3 per bAtk

for example replacing rstr with (rstr *2) provides 2atk per str:

 str = (int)((rstr*2) + (float)dex/5 + (float)st->luk/3 + (float)((TBL_PC*)bl)->status.base_level/4);