Oh I love me some tall caps. SA is guud. MT3 (ugh, Drop) are more favs. Did the case have any rebar-type material? I would think the tray mounts would have been metal. I would have welded/soldered some metal onto the standoffs and embedded them into the concrete for better stability. Any mount gets a huge amount of pressure from striking keys since the pcb is trying to move. Maybe I can figure out a 2 piece method and really get some decent rebar inside. Got a pic of the mason?