I’ve trimmed the dowels, tightened and trimmed the zip-ties, vacuumed the rug, and placed the litter box and toys (a chew-safe wooden key for tossing, a woven willow football for rolling, and a banker’s box for hiding, with two doorways in it and a grass mat for scratching)… this baby’s done!
Okay, so it’s really a work in continual process — I’m prepared to make adjustments once it’s filled with rabbit (who knows what he, she, or they do with the thing!?). But, for now… it’s done!
I secured the grass mats with zip-ties. I was a little concerned about him catching his nails — after all, these mats are for digging, to distract him from the linoleum and carpet (that, and for the sake of secure footing in jumping areas) — so I kind of wove them into the middle to hide them, and used as few as possible, just enough to keep the mats in place. Mostly I tied them to the cage bars, but in two spots I had to drill into the flooring and tie them that way.
To cut the bounciness of the top floor, I secured the jumping ledge (the most bouncy part) to the dowel and cage with a zip-tie — that’s through both linoleum and plywood (I drilled a hole), but underneath the grass mat. Otherwise, I didn’t attach the floor to anything; barring a giant breed, I don’t foresee problems — and for many reasons I can’t accommodate a giant breed anyway.
All zip ties are pulled so taught and flat that I don’t think they’re a threat to well-trimmed nails.
I secured the top dowels to the roof on each end and in the middle, wrapped around the dowel but not drilled through; they still may shift a little with vehement shaking, but there’s no way they could fall now.