if you are going to lvl a THM, dont lvl a con just for theyr elemental spells, you are a thm your scourge,banish are your gods and the fact they draw power from mnd and not int like elemental spells makes you into a type of hybrid and puts you in a plane of strnegth that the conj cannot reach,
if you are going to be thm lvl conj for his heal and his MUST HAVE its not if you want to or not its MUST HAVE Protect/Shell and if you can get to lvl 20 because the cure2 will help you alot aswell, after that you are ready to go back to thm stronger than ever, wth all thm mp restorative abillities you now also have Spiritbind which i dont use and dont have any mp issues but if you want to use lvl 2 damage spells Spiritbind is a MUST.
there are other bothersome ways to keep your mp up but nvm that lets stick to the class.