You are think of the CPP not the CPE which I have. It's the small model.
I'm happy with my results with D76 and T-Max RS. Xtol worked fine back when I tried it too but didn't do anything that special for me and I don't care for 5 liter powder mixes.
Worse heresy is that I've tried Rodinal in years past and was never able to get results I like with it. I have some to try again, probably inversion not rotary and I may have to limit that to winter.
Thanks for the clarification!
I don't think Rodinal is a good developer for rotary processors. The main reason to use Rodinal is to get accutance, and that requires minimal agitation. With continuous agitation, the negatives will be flat and dull.
Back to the OP, though: I think it is better to change one thing at a time, if something bothers you. If HC-110 and Acros didn't work (for good reason), then why not stick with HC-110 and try TMax100 or Delta 100? Or alternatively, stick with Acros and use a compensating developer. In my view Acros is a very fine film, and is the most affordable in 120 format at the moment, although the difference is not big and certainly not that important considering all other expenses. Developers such as Rodinal and HC-110 that can be used one-shot are very attractive to me, because it is far quicker to get the temperature of the water correct prior to mixing in developer, than getting pre-mixed stock solution to where it needs to be by immersion in cold or warm water baths. If you have perfect temperature control, that should not matter, but for me it is a great time saver. Apart from that, those developers last very long, and give fine results if used in the right combinations.
As I've said before, Rodinal at 1:50 with Acros gives me very good results. I don't do stand development, as I cannot control the temperature well enough over that period, and we have very widely fluctuating ambient temperatures. 1:50 is a good compromise that gives good results. By all means try Xtol too. I would be very curious about your impression comparing let's say Acros developed in Xtol, and in Rodinal. Only if you have any inclination towards such a comparison, of course.
EDIT: I forgot to mention that Acros in Caffenol can produce very good results too. It would also give you a useful speed boost over Rodinal or HC-110. You'll have to experiment to find the best set of variables, becuase Caffenol is an "unofficial" developer. But it certainly works very well.