I have a Pedaltrain Board and I just mounted my H9 Max. I just put a layer of velcro (hook side) onto the bottom of the pedal and it seemed to mount just fine. The feet on the H9 don’t seem that high to moe and there is enough bite on the velcro that I am not worried about it holding. I was mainly worried about messing the feet up and not knowing whether I could get replacements or not. In any event, I think I’m good. Good luck with your set up!
Mike
