I'm trying these spells out at level 25 instead of 35.

I have one or two balance concerns about this; we'll see how it goes and adjust from there. Overall my thoughts are:

1) Even the best mage PK builds at 25-30ish are usually much less common than, say, PKing warrior at those levels and

2) The duration on these spells is level-dependent, so at 25 you're still paying as much mana as you are at 35, but duration-wise you're getting less out of it. The recast timer also is fixed so, again, you're able to keep this spell up, even ignoring the mana cost, less at 25 than at 35+.