I think an FZ6 is a great bike! That was a top one on my list! I also think it'd be fine for you.

Just want to mention tho that it is definitely in a different league than sv650, gs500, and 650r. All those bikes are twins very linear horsepower. The fz6 is an inline 4 that is peaky but still makes great power all over!

Gs500 ~ 50hp
Sv650 ~ 70hp
650r ~ 80hp
Fz6 ~ 100hp. Power plant and power from a fz6 will stomp this competition lol

I think it'd be fine for you tho!