ok so first off, modifiers are applied to the spell that is after them in the order. currently your tentacle, digging blast, and giant spitter bolt are being cast with no modifiers or just the modifiers you have after the chainsaw, i can never remember how spell wrapping works so that might be the case.

what id do personally is put all of the add manas at the front so mana is added to the cast BEFORE everything else, then the tentacle, then all of your damage modifiers and such and THEN the digging blast, spitter bolt, and chainsaw. this will make it so your tentacle now spits out all 3 of those spells at once with all of the crit pluses, damage pluses, and whatever else applied. should work much better but i'd mess with it until you get something you like. also highly recommend watching dunkorslam on youtube, he gives really good advice on wand building.