Brian,
i used to develop all my color 4x5. here are some personal observations:
developing color is a multipart process, longer than b&w. it is extremely temperature sensitive. i personally do not like using jobo, at all, i always did all my development by hand in trays. if you do that, definitely use gloves; color chems are more toxic (and you will feel it on your hands). as with b&w sheet film, you need to keep rotating it, which both agitates and prevents it from sticking to each other. if you will use trays, you will need to place those into a larger tray (i think 11x14 was sufficient), into which you will have constant inflow of hot water, to stabilize the temperature. if you are developing at 90F run your warming bath at 95F or so, to compensate for transfer through plastic trays (if you have metal trays you can omit this part). i suggest you first try doing color on 120 film, in which case metal developing tanks are the (only) way to go. also, color chemicals have a shorter shelf life (from my experience) than b&w chems; i suggest buying smallest batches first. if i remember correctly they last <6 months from the time you open them.
good luck.
bibiana