Glad you posted your houses Brian -I think I need to do the same thing (several smaller houses instead of one large). I'm getting rid of my reeds after this year cause mites and other parasites will build up in them over a few seasons. The cardboard tubes that a few sites sell (like Crown Bees) work well, but can get expensive when you have to put out several hundred. Looking for a cheaper way to raise them and cut down on the parasites. I've used blocks that have holes in them, and that come apart for cocoon harvesting and cleaning but they have a tendency to warp.
She's seen better days

I've added more tubes to the top chambers, and replaced the full ones. Also have a small plastic bowl close to the house with some mud in it. They build out the chambers faster if they don't have to go looking for it. They also don't seem to mind me getting close for the occasional photo: