Iford sold a line of processors that could be used for RA4 and Ciba and might also be configurable for RC B&W. I have used an older version that was dedicated to B&W and it was very hardy and had a 20" paper path. The base unit I believe was made by Thermophot.
I have used a similar small table top made by fujimoto that also had a 20" path. I don't know if the fujimoto was configurable for cibas and it did not seem as well made.
Your point about chemistry is right on. Mix a little bit more than what you need and print until your done. If you have chems left over and if you can displace the air in the replenishment tank it will easily last a a week or two.
Run water through your replenishment system and processor until the taste is gone.
(kidding about the taste thing)