4ply mat board warping

[bobcorn]

I am using PVA glue to attach paper to 4 ply mat board for hard binding handmade books. As the paper dries the mat board warps. What are the best strategies to prevent or correct this?

Could not find this addressed in the bookbinding books I own and online searches have failed me.

Thanks!
Bob

[bookbum]

Two thinks I can think of:
1. Make sure the grain of everything is aligned.
2. if you apply something to one side of the board, you need to apply something to the other side with an equal pull.