Well, you said you wanted to be a Runecaster dude its not optimal but certainly workable. in any case i never really liked c3 linker, c2 covers whatever you need really.
Better choice would probably be warlock, even though c3 sorc is iffy? you might be best taking sorc 3 so you can get the extra 38% summon damage out of your summoning skill max familiars for esploding goodness and a decent attack with 8seconds cooldown. Remember you won’t be that active anyway you will probably just be linking people and letting your summon do most of the work.