Since you test and make curves, the best advice is to use the speeds you find from your tests. If you have calibrated sensitometer, it will be obvious. If you have a home-made sensitometer that is consistent, but not calibrated... Set the box speed to agree with the curve that "best" fits the ISO parameters where you used a standard developer.
Originally Posted by AndreasT
Having done that. Then look at the curve of the film/developer combination you intend to use and use Delta-X criterion to arrive at the EI for that curve.