It sounds like you had a problem and figured out how to solve it. I agree with the saw horse issue under plywood. I had five saw horses and a bunch of 2x2’s notched so they would not shift to hold the plywood off the saw horses during cuts primarily from plywood issues. And they were both length and width pieces. I adjusted the saw horses height with the 2x2s on top to also serve as in-feed and out-feed tables for the table saw. Clamps on the legs held them in place. However, my wife works better than they do. So the assembly went off to a neighbor for one of his construction projects.
I suspect smaller, possibly several 2’x2’ of foam may work almost as well and be easier to store.
Like your solution and will definitely keep it in mind as a pass along to others.
Thanks for the info.