Using Kodak RA/RT Developer Replenisher and Kodak bleach-fix you can process at room temperature (68-75F) with excellent results with Kodak Endura and Fuji Crystal Archive papers and my guess is Arista papers would work as well. This allows you to use trays and makes print processing about as easy as it can get. I use just developer and bleach-fix with no problems. I used drums at one time at high temps but after switching to trays my productivity increased greatly. It was a time waster having to wash and dry the drum after every print and different sized prints weren't easily made. And why have to fool with temperature control? Trays at room temperature solved those problems. The RA/RT has a long life, even in trays. After a printing session I pour the developer back into a glass bottle, full, tightly capped and save it for the next session. Depending on the length of the sessions I can get several sessions before the developer expires. You might try the Arista developer at room temp and see if it works. You should use whatever method works best for you but just letting you know there is an alternative method used by many Apuggers.