I have an 8x10 Nova slot processor (each slot 1 liter) that I'd like to keep full of a working solution of B&W developer to process a few sheets a day of 4x5 B&W sheet film over Christmas vacation.

I have already HC 110, Rodinol and a couple of types of Ilford and Kodak powder developers (ID11, D76, Microdol-X).

Which of these (feel free to recommend other - although I tried Diafine once - not too keen on it) that will keep for a long time (3 weeks) in working strength and still be reliable?

Thanks in advance.