JMHO:
Make it only as long as the shortest piece of the MHS - currently 2.5 inches. Height should be around 1/2 inch, and width should be around 1/2 inch.
I think that a plain rectangular box would work best initially, perhaps smoothing off the sharp corners ever so slightly so they don't catch on anything.
The tops of the box could easily be modular. Whether they slide into machined channels on the box (easiest), or bolt on.
Here's a sketch. Probably easier than trying to discern meaning from my post:
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