How does it feel versus the case with the silicone foam? Would you recommend finding some to put in there? I took it out of the case and tried it on some electronics packing foam (read: the foam covering it came with out of the box) and I like how quiet it is versus with the case.
EDIT: Also, do you think I should use some stand-offs or just screw it into the plate?
I did notice a little bit of a difference with the silicone vs not. You want pretty soft silicone. If you do this, I would actually recommend a closed cell silicone foam at about 20-30 durometer. Since you are distributing the pressure across the whole board, you need a really soft durometer for it to be noticeable. The difference is very subtle. On the non-silicone board it basically feels like a standard aluminum/steel plate. On the one with the silicone layer it is a little bit quieter and the bottom out feeling is not quite as harsh. Keep in mind I have only ever done this with an acrylic plate.
If you are using an acrylic back plate of about 5mm, I would just tap the acrylic and screw directly into it. I have done a lot of testing of different ways of doing it and this method is pretty good. If you are using an aluminum back plate then I would recommend using a non-conducting layer of foam. You may want to cut out areas in the foam layer to accommodate for taller components, like the USB port and the reset switch and such.
What I am currently using right now is a 5mm acrylic back plate with the PCB screwed directly into the plate. However, I have trampoline modded all of my switches. The trampoline mod is done by placing a small silicone ball in the base of the switch housing tube so the switch stem hits the ball on bottom out. This gives basically the same feel (if not more) as using a silicone layer.
