Try it out,
Capacitor discharge is Temp related, but i haven't seen anyone go under tRC*6 , *5 should be possible but i haven't gotten my hands on anything to work personally on recently
Voltage should only increase heat - it will increase the amount of charge and up to your timings, more will be left
But then higher heat has a negative effect and they will lose even faster the charge
tRP is there to adjust and help on this "issue"
If your dimms get too hot, increase tRP
If you want less vDIMM, increase tRP
if you want to meet a tRFC target, decrease tRP and increase voltage
Only increasing voltage won't really grant you a good tRFC ~ as neverless what fixed refresh-cycle-delay you pick, tRP same as tRAS has to pass before anything can happen. The same goes for tRC, nothing will happen till that one elapses and tRAS being the only one that is autocorrected if it's ACTIVE timing ends up being too short.