All plywood at this telescope is Baltic Birch. They are removable for transport and storage. The mirror cover sheet is placed directly above the mirror leaving storage room for the altitude bearings, finder, bolts, eyepiece case, warm socks, chocolates etc. I store the telescope like this and thus be sure, not to forget anything. This is so strong, it stabilizes the whole mirror box.
Radial support is done with a car safety belt.
At the back side a ring baffle is inserted to prevent light leaking between mirror and box walls. The air can still circulate to cool down the mirror quite rapidly. This method is very stable and keeps collimation, but requires to screw and unscrew the 8 clamp knobs. Here only a tightening an untightening of the clamp knobs is needed. A friend with a lathe helped me, to make the bores of this blocks, thank you Gert.