Hello ctpres - don't know if it is coincidence or you saw my recent post, but I'm very interested in seeing your holz hausen 'building' pics and particularly (hint, hint ) your 3mo. efficacy follow-up review. Are you starting with freshly split green hardwood?
I put down galvanized metal roofing and overlap it until it completely covers the wood area. Then I pile the wood on top of that. The bugs can't get through the steel and it keeps the wood clean, too.