Hey Will,
Nice setup you have there.
I’m a DIY guy to a fault. For starters, I’d put the keyboard up on the desk, cut some strips of cardboard and layer up under the back of the keyboard until you get the height/angle you want. Live with it a few days as it will give you a lot insight to what you really want, which maybe something totally different. Once you decide on the angle, make some wedges; wood (my fav), cardboard, foam packing material, etc. Wrap the wedges in; black duck tape, fabric, or paint black (black blends in and shouldn’t be noticed under the keyboard. Possibly put some non-slip material on the wedges if necessary. Could also use those wedges from your Auralex speaker pads. Take the 50 bucks you save and buy a lava lamp 
Just my 2cents,
John