There are many people who experience pH rise in newly plastered pools. I think that this pH rise can be greatly reduced or eliminated by maintaining a CSI of 0.0 to +0.3 and by using a pH in the 7.7 to 7.9 range when the CSI is going to be kept slightly negative for some reason (such as using a SWG).
The initial pH rise is due to the formation and release of calcium hydroxide Ca(OH)2. During the first 30 days, most to all of the calcium hydroxide in the surface of the plaster should become calcium carbonate CaCO3.
Ca(OH)2 + HCO3- <> CaCO3 + H2O + OH-
As long as the CSI is equal to or greater than 0.0, then the calcium carbonate in the surface layer should remain passive. If the CSI is less than 0.0, then the calcium carbonate will continue to dissolve into the water, which increases the pH. This will also expose calcium hydroxide in the underlying plaster, which will also cause pH rise.
Even though plaster will continue to cure for many months, the plaster below the surface should not affect the water chemistry as long as the passivation layer at the surface is undisturbed by either dissolution or by mechanical abrasion.
The rate of pH rise should be a function of how negative the CSI is and the pH. Since the calcium carbonate is largely attacked by hydrogen ions, the concentration of hydrogen ions should be a primary factor.
CaCO3 + H+ <> Ca2+ + HCO3-
For example, if the pH were 7.8 and the CSI were -0.1, you would have some pH rise due to the dissolution of plaster. If you lowered the pH to 7.2, then the CSI would be -0.7 and there would be 4 times as many hydrogen ions. The concentration of carbon dioxide would also be much greater, which will increase the rate of pH rise due to the offgassing of carbon dioxide.
Due to multiple factors, I think that the rate of pH can be greatly reduced or eliminated by maintaining a CSI of 0.0 or higher. If there is some reason that the CSI is kept slightly negative, then a pH in the 7.7 to 7.9 range should be especially helpful.