Hack suggestion of the day. On top use an oversized KO and just use one reducing washer, locknut, and a bonding bushing. The bottom can use a correct KO and a locknut. Once the bottom is secure you can tighten the top.
I have done dozens of them as we used to be a pipe and wire town,
Secrete is not to be afraid if injuring the wire.
Two, most of the time you cac push the top conduit up an inch or so.
You will have to get good at "scoring" EMT and snapping it off if you have a few inches to work with.
I had this in a concrete block wall. Luckily the webbings weren't poured. My panels were nearly identical in size. If you can find the first jb in a run close by, pull the conductors back to that point. The pipes are hard enough to deal with, limit the amount of wires you have in the way. If you can undo any couplings and transition to flex. It makes it easier than hard pipe. Male adapters, ridged couplers, threaded nipples and lock nuts can be your friends too. Good luck, remember "Where there's a will there's a way!"
I like 480's suggestion the template idea ain't bad either. Using flex could be helpful too. I got one where there are emt branch circuits on the top and the 125 amp PVC feed is one the bottom. Might just open up the wall a bit drywall is cheap right.
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