My apologies- I somehow missed your message two days ago.
It sounds like an interesting idea, but probably alot of trouble. I have my houses on a pulley system so that I can raise and lower them without getting out the 10 ft ladder. I started a thread with pix of one of the houses I built, and there's a couple more on my profile page in my album.
I just use hole plugs during the off season. I'd love to see photos of the house you mentioned. Is there one available online?
Edited to add: Keeping the holes covered during the off season only deters starlings and sparrows, then when they are opened back up, they will converge on the housing anyway. Imo, control is much more effective than deterrence.
