Two stacks of nailed together 2x4's would suffice. No need to get fancy. 2x6's would be more stable, but take more room. A "leg" of 2x4 off the stack would stabilize it well enough. I want to do it because of trouble coming off the floor, at the 3" point. I still don't really understand how SKIPPING the trouble spot makes it stronger, but who am I to question the guru's...?