I wanna start working on turning my Thief/Assassin more into a Nightblade now that he is level 34. Question is what route should I go on Illusion for a Nightblade?

Also how should I approach attributes. This is what I have at level 34 for Base attributes:

100/380/150 (Should i go more stamina and Magicka now?)

Mostly I tend to use Dual Wielding 1 Sword and 1 Dagger when I'm mixing it up with enemies if I can't sneak attack them with my Bow or Dagger. Currently using Nightingale Armor set as I'm finishing up the Thieves guild for the first time. I can post what I have for perks so far if needed.