I'm not exactly an expert (I've started doing E6 less than a month ago, and have done exactly 4 rounds so far ) - but I'll try to help with what I know.
Use whatever is easier and quicker to set up...
How many rolls at a time? One by one? Three-four 120 films at a time?2) I plan to process 35mm, 120/220 e-6. What drums should I purchase for these formats?
The drum size depends on that. I'm not sure I get your "20 rolls once or twice a month". At once? There's no drum big enough for 20 rolls at once - and even if it were, such drum would be too heavy for the Jobo lift, I think.
Don't buy the biggest you can, thinking it might come handy. The bigger ones use more chemistry, and are not very practical for 1-2 films.
Attched is a one-page PDF with the list of Jobo drums. See for yourself which one would suit you best.
I don't have any experience with the kind of processors you have - like I said, I use CPA2, and I have to use a separate plastic bucket for keeping the rinse water heated properly.3) I assume its best to have a small hot water heater near the processor for best temperature control. Any recommendations on which one to buy? The feed water is Reverse Osmosis, so glass lined would be ideal.... I would think..
Hmmmmm.... not exactly, I think. If you have some kind of local waste treatment facility, I think it would be preferable to just dumping everything down the drain...4) OK for all e-6 used chemicals to go straight down the city drain?
High volume only, I'd say. The volumes you mention are not really "high" enough for that.5) Is silver recover recommended, or is this only for very high volume processing? Any inline systems you can suggest?
More or less. I use Fuji chemicals, but only because I couldn't find Kodak ones locally. Regarding the Fuji/Kodak FILMS difference, the general wisdom is that Fuji films require about 15 seconds more in the first developer: i.e. if the normal time is 6:30, then for Fuji films 6:45 should be used. I've followed that "general wisdom", and got OK results.6) I will be processing Fuji Films, is there any advantage to using fuji chemicals? I assume they are identical to Kodaks?
The stuff I've read BEFORE I tried anything:7) In another thread, "Kompressor" mentioned some Kodak chemical he purchased contains an excellent instruction booklet on the details of e-6 processing. Is this booklet available in pdf format anywhere? Or, if there is other "must read" e-6 processing information, please advise..
1) Fujifilm Technical Info Sheet: 3E6 Processing Kit (PDF)
2) Fujifilm Technical Bulletin: Process PRO6 (PDF)
3) JOBO_E-6_Handbuch_GB (the one I linked in my previous post)
4) Kodak E6process pub. #J83 (PDF)
5) Kodak pub. Z99 and Z119 (PDF)
There's more, I'm sure... But those should keep you busy.