I have been asked to build a platform that will be roughly 5 foot by 3 foot. It will sit on a sloping floor. The back of the platform will be 12 inches off the floor and the front needs to be 14 inches off the floor in order to be level. I plan on building the frame out of 2×3s or 2×4s with a 3/4 inch plywood top. Has to be strong enough to hold two adults. My question is what angle do I need to cut the support braces for the frame. Hope this makes some sense.