Hi, my name is Tim, I'm building a bench for my daughter's dorm and it seems like the front apron is very weak. Its a 1x4 with curved profile making it 2 inches at its thinnest. It flexes up and down when I put pressure on it. I do plan on putting cross supports on the bottom like I did on top. My question is will a 3/4 ply seat board give it enough strength, or should I replace the apron with 2x material, or is there a better way to give it more structure? Thank you for any help