Im trying to gain confidence to do my first E6 development and this with Fuji Velvia 100F 4x5" sheet film. However I am uncertain how to choose processing time.

I will be doing my E6 in a Cibachrome drum for 8x10 sheets. Where minimum of 75ml and maximum of 100ml of chemistry can be used. I've used this for B/W development before and used constant manual rolling agitation in a waterbath. If being carefull 2 sheets can be processed simultaneously (there is no separator for 4x5" sheets).

Listed time for first developer is, if 500ml solution is used:
6'15" for first two rolls, 6'30" for the next two rolls and 6'45" for last two rolls¨
And if 1000ml solution is used:
the same times but using four rolls instead of two in the tank each run.

Can I assume linearity, extrapolate and use the same times using 100ml of solution each run and with sheet film corresponding to the same emulsion area as 2/(500ml/100ml)=4/(1000ml/100ml)=0.4 rolls of film and do 3 runs before disposing the chemicals? Similarly for the other baths. I guess I could use one-shot chemicals but also the chemistry is expensive in Sweden.

What is the area of a 36 frame 135 film or a 120-film? I remember T-max RS used an equivalence of 1 roll of either 135 or 120 film corresponded to one 8x10" sheet in the replenishment rates. Can I assume the same here?

What is the rotation rate of rotary development systems that I'll try to mimic?

Lastly, I've heard somewhere that Fuji films should use extended development times in Tetenal 3-bath E6 kit as compared to Kodak films? Can anyone confirm or dismiss this? I guess it is reasonable to do this kind of pushprocessing for Velvia 50 which by many are rated lower than 50 but I've been told that Velvia 100F is truly a iso 100 film. Anyone tried this combination of Tetenal 3-bath E6 and Velvia 100F in particular and can share their findings?

Again I could try and see but I am trying to gain that extra confidence before starting and sheet color transparancy film and E6 chemistry is quite expensive so I'd prefer getting it right the first time. I am so looking forward to watching that first 4x5" slide on the lighttable.