Pedestal Seat Base

Ok, hopefully this question has not been asked too many times. I plan on placing plywood on top of my rear seat and attaching a pedestal base using toggle bolts. My plan is to attach the plywood with 6 toggle bolts, 2 on the left, 2 on right, and 2 in the middle. My question is should I just attach my pedestal base to the just the plywood or should I attach it through both the plywood and seat, which would require additional toggle bolts? Also, I used 3/4" for my front deck, should I consider using 1/2" for the rear or stay with 3/4"? Thanks in advance and I'm sorry if this questions has been addressed before.

I'd consider just using some extreme duty construction adhesive to hold the plywood to the seat top. The toggle bolts will work but I don't think you'll get a lot of stiffness unless you place them as far out as possible. Using both would certainlty work as well.

Jamie