The only relevant Jobo documentation on this sort of question, as far as I could find, was in their "Expert Drum" guidelines. For 4x5, they suggest 33ml per sheet (C-41/E-6) or 50ml per sheet (B&W). For 8x10, they suggest 126ml per sheet (C-41/E-6) or 200ml per sheet (B&W). You can sort-of extrapolate to something like 1.58-1.65 ml per square inch of film area (C-41/E-6). Doing that math out roughly, and rounding up, you get around 120ml (C-41/E-6) per roll of 120.
Now Jobo basically recommends using the maximum of their per-film numbers and the minimum capacity of the tank. However, that factor really only kicks in with the Expert Drums (or the paper drums).
The number I attempted to derive above is less than the minimum rotary capacity of any of their tanks that can process 120. So you're probably fine.
(The smallest rotary option for processing 120 on the Jobo system is the 2520 half-full at 170ml with a single roll. I've actually done this with C-41 before, and the results seemed to come out fine.)
Now Jobo basically recommends using the maximum of their per-film numbers and the minimum capacity of the tank. However, that factor really only kicks in with the Expert Drums (or the paper drums).
The number I attempted to derive above is less than the minimum rotary capacity of any of their tanks that can process 120. So you're probably fine.
(The smallest rotary option for processing 120 on the Jobo system is the 2520 half-full at 170ml with a single roll. I've actually done this with C-41 before, and the results seemed to come out fine.)