Thanks Mike, that is quite helpful. The kit I have seems designed for use-to-exhaustion rather than replenishment as the instructions give an increasing-times-per-roll table and no replenishment rates.
Good to hear that the concentrates keep when separated from air, as that is my plan. I'll be mixing up 0.5L batches and doing 5 rolls in each. I have heard from a couple of lab operators that the (preservative in the) Fuji pre-bleach does die quickly once mixed and that you won't know it's dead until the film starts degrading on the shelf after a few months.
The kit has dev capacity for 44 rolls and bleach/fix capacity for 2-3x that so if concentrates do keep well and I don't decide to go all C-41/RA-4, I'll just buy more dev concentrate on its own. As it is, I shoot 6x7 and larger so projecting chromes isn't really happening for me at the moment