All c-41 kits are not equal, and a liquid, single part mix, long lasting system is what you want, one shot is always best to minimize the chance of contamination. One drop of bleach or blix in even a very large container of color developer, will make the whole batch unusable.
Omer, does your kit's instructions tell how to extend the time when re-using? Because of the size of my tank I will have to use at least a liter of fluid for each step. This would be for 12 4x5 sheets or 5 35mm so one-shot would be prohibitively expensive.
A politician is a man who will double cross that bridge when he comes to it.