I’ve been fairly pleased with with Grey, Tough 2000, and Rigid 4000 in terms of quality/accuracy.
My 3L also sometimes goes months in between prints. One big challenge is the tank lifetime after resin is in them. I’ve had a couple 3L Tough 2000 tanks leak (once earlier than expected) with barely any prints. If you’re not using it regularly you might want to look at the resins that aren’t subject to an exposed-to-resin time limit, like Standard or Tough 1500.
I’ve been doing a lot of plain Grey lately and it’s working well. Of course it will depend on the tolerances required by your project. If you can do direct-on-base for some parts you should get decent accuracy in the X/Y dimensions.
Model resin is supposed to be optimized for accuracy (although is also subject to resin-exposed lifetime restrictions). I’ve never tried it myself, but might be another one to test.
I use either one of the Tough resins or Grey Pro for my functional prototypes. All depends upon what I need the part for but basically I have found those to be the most dimensionally accurate, with Grey Pro being slightly better.