I really newb'd it up on the background, mostly from being impatient. The foam expanded more over night, did not anticipate this. I had to shave excess foam off to get the background to fit. Tested it out, fits OK but the back did warp a little, so the back is not perfectly flat.

I will need more silicone to fill in the gaps and then add more peat moss. Once the background is finished and cures I should be able to slap this all together. Heading out to get more silicone now..