Why plan for a bigger case? I'd suggest scrapping the 84 hp skiff and moving up to something MUCH bigger. This would be good: https://www.ericasynths.lv/shop/enclosures/studio/1x126hp-skiff-case/ Has ample power, still fits the 1 row form factor. But at that price point, you could also step on up to a 2 x 104 hp Mantis, which is also powered but is even beefier on that aspect than the Erica. Plus, Tiptop has a mounting bracket that allows you to tandem TWO Mantises into a four-row configuration. This seems more sensible because of that as well; if you find that you want to expand the Eurorack to more than just a sidecar for the Moog, this sort of advance planning is critical at THIS point in the process...don't try to retcon your case configuration in mid-build!
Oh, and if you do go to something larger, DON'T put the M32 in it. That's a waste of money, tbh, since the Moog already HAS a case and power...and those Moogs work nice together, so keeping it in its 60 hp cab for later Moog expansions would be a smart move.