Detecting skills already learnt?

I need a li'l help here on a map I'm makeing I wanted to make the level ups depending on what skills you learnt for example

starter guy would have

bash
cold arrow
summon water elem
chain lightning
holy light

now if on lvl 5 he made bash lvl 3 and had at least one point into holy light I wanted to replace the unit with a new character that would be a fighter/healer

but I cant figure out the triggers for detecting the skills that are learnt or what lvl they are

so if anywon knows how to do this and is willing to help , or if anywon knows it isnt possible please tell me thnx

Event - Unit Owned by Player or Specific Unit Event (Unit Learns a Skill)

dont use a condition

If (Hero Skill Comparision) Learned Skill Type is = to whatever then set varible (some interger varible) = to arithmatic (value + 1)

repeat for all skills, use the value of the varible (i suggest you use an array) to see what level the skill is