104* or 108* ??

Yeah not huge gains for sure but with only 9.2:1 I would shoot for more advance. With a tall gear you want brutal TQ to move the car and have it "feel" powerful and advancing that cam 4 or 5 degrees would do that.
I'd bet you could feel the difference and to me that's enough.

Like I said earlier, if the comp. was higher or the gears were lower then I'd agree maybe only 2° adv. or straight up.