Hi Everyone - This is Richard. My partner Matt and I make the Wally Rebounder and saw it mentioned in the thread. Jake, Awesome videos showing your skills with the board you are using!
Obviously, I'm a bit biased on this one, but return boards are a great way to develop some skill and build consistency especially when a partner or coach is not always available. Matt and I are also big DIYers and fans of cool DIY projects - we've seen a few DIY return board builds that are pretty nice. It's useful to be able to position the board behind the table so I would advise some kind of stand vs. just setting the board on the table. Playing around with different rubber is fun, but for a basic build, you can find some decent Chinese rubber online for several bucks each and put them on a fairly high density board (hardboard with a stiffener works well as does high density plywood like baltic birch). - I've seen a few people use TV/monitor stands as a way to hold the board and a few others use hinges for the tilting with some mechanism to lock it in a various tilt angles. Also please make sure whatever stand you use or build is stable and won't tip over with the board tilted in different positions.
Anyway, I wanted to introduce myself and contribute to the discussion. If you have any questions about Return Boards in general or about the Wally Rebounder feel free to PM me!