What I used: Floating shelf brackets, latex non-slip adhesive that can be cut with scissors, and velcro. Velcro to attach the amp to the bracket, and the latex making contact with the amp surfaces. In total it cost me about 25 USD. I wanted to minimize any change the amp or cab, and seems like a bit of velcro adhesive left on the bottom of the amps is the most likely (very minor) issue.
I can tell you they are on there pretty snug, as gravity pulls the non-slip latex against the front and top of the cab.
It's possible i'm the only one who considers this a thing worth doing, but I figured I'd share in case it's useful to somebody else.

I can tell you they are on there pretty snug, as gravity pulls the non-slip latex against the front and top of the cab.
It's possible i'm the only one who considers this a thing worth doing, but I figured I'd share in case it's useful to somebody else.

