Your Jobo is probably the best solution for you. There are developers that
are slower working but not weak that you might use. One of Ansel Adams'
books, The Negative is a good resource also the Ilford Manual of Photography.
Another solution is to try Ilford's XP-2 sheet film which is developed in
C-41 chemicals at a pro lab. One can use 2-bath developers with the Jobo, or
if your dilute developer runs out of reactivity, you can refresh with new
developer half way through. Keep the Jobo.
Best wishes,
Lynn