Id like to ask a question regrding my future characters abilities: is it okay for the mana expenditure to be decided in combat when regrding healing powers? Currently, im thinking of having the cost of healing increase with the amount of organic tissue required to restore and reseal, but that means that the needed amount of mana can't stricly defined and has to be decided on spot, depending on the severity of the wound.

Listing the cost per gramm and cm^2 would be a bit too much, at least for me. I dont want to be all "count, count, rinse, repeat" every time my char heals.