Rapid fixer lasts a long time, does around 20-24 rolls per mixed 1+4 litre of working solution.

HC-110 is good for long shelf life, as long as you use it from concentrate (ie. Don't make a stock solution). DD-X or ID-11 may give slightly smaller grain, different tonal curve. Microphen works very well too, let's you shoot HP5+ at 500 EI.

You still need Final Rinse/Stabilizer with new C-41 films. Distilled water is not enough.

I too can only order Kodak chemicals in 40L quantities so I've been using the 3-bath JOBO kit that PE does not recommend. It works for me, sounds like I'd get lower grain and contrast with a separate bleach step. It is supposed to last a long time and I do shoot around 100 rolls/year which would use up 40L one shot in a year or so but it still seems like a lot to keep on hand.