A pool that is enclosed as yours, with a VSP running at lower speeds, as yours, even with a Florida filter (notoriously small) should not have to have the filter cleaned more than a couple of time a year. We clean based on a pressure increase, which needs to be measured at higher pump speeds for more accuracy. The recommendation on this site is a 25% rise over a clean reading. Manufacturers say an 8-10# rise over clean.
Cleaning is how cartridges wear out. Cleaning a "clean" filter is wasting your time (that could be spent in the pool) and water.
If the 60% mark works for you, then it is good. Its just a starting point that may not need to be changed. Since your pressure reading seldom changes, the 50% rate may work well for you. All pools are different.
I’ll try 50 % for a few days but it may not be enough if the PSI changes. I’ll keep a close eye. I’ve reached out to my PB to set my pump so it clicks to best setting when the heater turns on and back when it turns off. But for now I’ll play around a bit. I’m very grateful for your help.