I wanted a quick to print atx mount that wasn't overkill like all the others I have found for the anet am8. I designed and installed it on my am8 and it works just great. Will take some photos later of it on my printer. I found that I didn't need a bottom mount because the bottom corner of the psu rests on the corner bracket used to mount the z extrude to the base and this was enough to prevent it from moving. I will probably create one small mount to support the other corner, so that it does not wiggle when you unplug the atx or anything but I am not in any rush right now.
3 outer layers for walls. I would use minimum 40% but more won't hurt.