Elk M1 in a Leviton Can

[sda]

I typically buy a SYS4S kit and then get a 28 to go with it. Use the smaller can for oddball system components, subpanel or battery can on the larger systems, couple of stubs of pipe or close nipples and you're done. Instant 42" Elk can if you really want to be in the same stud bay.
 
Again, maybe I'm alone here, but I'd prefer to have a pair of enclosures side by side and piped together over a huge tall one.

 
In my case, I put a 14 under a 28.   The knockouts did not line up vertically and I couldn't just straight nipple them together..  I ended up using 1-1/4 pvc meter offsets so both covers would be flush with the drywall.  Wasn't a perfect fit, but darn close.

 

[Del91574]

I can't remember the exact way I did an over/under, it's been a while, but I really don't recall it being that difficult, but then again I'm used to dragging out the knockout set for work, so it's generally second nature.
 
I try to go side by side...I'm getting tired of stooping and controrting to work on panels as I get older.