Damn, OK.... thank you.
So I will need Nova specific seats?
Not necessarily.
I used the Camaro buckets. I did get this mounting kit:
http://www.autometaldirect.com/amd-bucket-seat-floor-brackets-69-71-chevy-nova-p-7635.html
and it worked well, the outboard brackets do not sit in the standard Nova location, they end up being further out board.
Set the hump brackets in place (don't weld them yet!) and loosely bolt the seats to them. Loosely bolt the outboard brackets to the seats.
Move the seats around a bit for best location and bracket fitment, make sure they are square to the world. IIRC I did have to trim the front outboard bracket a touch for a good level fit.
Tack weld the brackets in place and triple check fit before welding them fully in.
It was actually a very good solution for my 70, the floorboards were swiss cheesed by who knows how many different seat iterations through the years, the bracket kit gave me a good solid base.