From my practical experience with replenished Xtol compared to Xtol 1+2, which gives about similar activity, I have observed the following:
1. You can pretty much use 1+2 dilution times as a good solid starting point for replenished Xtol.
2. Replenished Xtol gives about 1/2 to 2/3 stop less speed than Xtol 1+2.
3. Replenished Xtol will yield sharper negatives, and a finer more acute grain.
4. Replenished Xtol, with its decreased shadow detail, will exhibit a different tonality from 1+2, giving more toe (less shadow separation) and a shoulder (less highlight separation). Midtones are similar in contrast to 1+2. I like this tonality better than the long straight curve, so I prefer replenished.
5. Replenished Xtol does not push well.
- Thomas