just so everyone else knows, I solved this by putting a pretty strong magnet inside the tray which then makes the tray stick to my inline Fab mount plate a little bit and not move around or fall out.
I thought about trying to recess one on the bottom but honestly this works well and it super easy since I have several options for good magnets anyway. I use magnets to hold Allen wrenches and stuff at each press or tool so I know which one is used for each item ect...
