Waste Board thickness with QCW frame

Hi all,
I have the dimensions to create the waste boards, and I am wondering about the thickness. I know it shows to use 3/4 inch, but could I use 1 inch? Any help understanding this is appreciated.

You could use any thickness you’d like, as long as the screws/bolts reach.

What is the minimum thickness? I have 6 sheets of 5/8” mdf that I’d love to use from, but the screws might be too close to the surface…