I originally started with square wood standoffs, but felt there was a little too much flex in the mount so I glued 3/32 plywood to the standoffs to form an engine box. I wasn't trying for the box at all and would have rather not had to add the weight but I did not have time to wait for custom aluminum standoffs.. so that is what I ended up with. Worked great and it was very strong.

I am sure aluminum standoffs would work fine.

DP