Hmm I was making some bad assumptions.
I guess Elans should state how much damage they will deflect if they are hit - perhaps just as standing rule for each character, that can be changed each turn./battle if necessary.
for instance Alberon has 11 hp, his rule of thumb is not to spend any on resilance, but if he is reduced to 5 or less than he will spend 1 psp each time he is hit.
the party is attacks an ogre so on his first turn Alberon changes his rules to spend 2 pts if he is hit. (btw) elans can spend psp = 1/2 hd or manifester level, whichever is greater, minmum 1.
Resistance can only be declared before hand, really since once the spell is cast its too late.
perhaps something like - if an opponent begins casting, are you going to use resilence or not?
This will make resistance less useful Im afraid. Any alternate suggestions?