Back in my day, boy, we did partial panel with nothing but manifold pressure and a hobbs meter....

[sarcasm]
There's any number of ways to handle this situation. The method the CFI used worked, so it's obviously one of the good ways. Going back to the home field, IMO, would've been fine too.
I'd caution on this though, you mention running through flows over and over.....watch out when single-pilot that you don't overwork/overanalyze a problem that might not be serious, to the detriment of flying the plane if you happen to concentrate on some part of the analysis. Example, if I lose my left generator while airborne, I can cycle the rocker switch up to three times as well as reset the CB in the cockpit. Right generator, I can do the same, but the CB is located in the nose, so once I run the checklist (all of one step) for that item, my analysis is done, nothing more to do if it doesn't come on line.
Remaining below the WX is an option and could be a good option, but you've got to consider what the viz is below the ceiling. If it's 1 mile and FG, you're probably better off climbing into VMC, since below the ceiling, it's IMC for your practical purposes on working an EP, especially if partial panel. Better to climb and get you eggs in one basket, than tool around down low in marginal and end up spatial-D close to the ground. If it's a ceiling with 10+ on the viz, of course staying under could be a great option, terrain depending.
There's many ways to accomplish this scenario depending on the variables involved. More info next time boy!