I don't bother. Everything one shot. RA4 chem is cheap. I use drums, so volumes per print are small,
even big prints.
My biggest concern is not that a pair of 18x24 cm prints needs 180 ml soup, it's the countless test strips I need to get the final print. Even the smallest test clips need their 80ml to fill the 2500 Jobo tank to min level, and it's these test strips which would make single shot RA4 unnecessarily expensive for me.
Trying to be the best of whatever I am, even if what I am is no good.