You might get some cracking if you try to bend it around tighter curves. If it's just straight it shouldn't.
I don't understand what you mean by support your benchwork? That's what the 2x4 legs are for. Did you mean stabilize the legs?
I primed the masonite before putting it on my benchwork. Will it now crack? If so, when would it happen and how can I prevent the cracks from showing through?
The other questions I had was how to support the benchwork since it's not being nailed to the wall? The legs are 2x4 supporting 1x3s in eight foot lengths
TIA!
Lee