Siiiigh... I just don't have the room in the corners of my box. The corners of the MB31s are pretty snug up to the corners of the box uprights. (Ref: a CAD I put together over the last week; I added some notional channel aluminum I found on Amazon.) I can cut big chunks out of the uprights I guess, (I hid one in the image to show the notional overhanging aluminum) since the plywood shell can certainly carry the minimal vertical loading of the box, but even then I'd need to figure out how to get my turnbuckles sorted and hooked up to... eye hooks through the angle iron or something. Still trying to brain this all.
Edit: Also struggling to find suitable extension springs at 500+N/m. Found a few at over $300/ea. Ugh.
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