You didn't state whether your water supply is municipal or private well. Private well water will not be usually chlorinated and therefore may contain ferrous iron and/or manganese which will also consume resin capacity in addition to hardness.
48,000 grains total capacity typically signifies 1.5 cubic feet (ft3) of softening resin, usually utilizing a 10" X 54" media tank.
For the best compromise of salt efficiency, water efficiency, soft water quality (low hardness leakage), and usable capacity per cycle, the usual recommendation is 8 lbs salt per ft3 resin (12 lbs total for 1.5 ft3), to regenerate 36,000 grains usable Capacity per cycle.
Assuming no iron or manganese, suggest increasing the hardness setting to 20-21 gpg.
Using 20 gpg X 525 gallons average/week = 10,500 grains capacity needed per week or 1500/day .
With 36000 usable grains / 1500 gr per day = 24 days - 1-day reserve = an estimated regeneration frequency of 23-24 days. Hardness reduction efficiency: 36,000 gr / 12 lbs salt = 3,000 gr/lb.
As I anticipate your WS1 will be equipped with a flow meter which will cause regeneration to occur just prior to the 36,000 grains being depleted, again, anticipating no iron or manganese present, suggest increasing the regen day setting to 30 which will cause a regeneration to be performed only when the 36K capacity has not been fully depleted within 30-days following the previous cycle.
You mention a 6 lbs salt setting which will increase salt efficiency slightly, at the expense of lower soft water quality (higher hardness leakage), and since a lower capacity setting will be required, the unit will regenerate more frequently, which will increase the quantity of water that is utilized for regeneration over time (per month/year).
6 lbs per ft3 will regenerate 21K grains Capacity per ft3 = so 9 lbs salt will restore 31,500 grains usable Capacity in 1.5 ft3.
31,500 gr / 1500 gr = 21 days - 1-day reserve = an estimated 20-21 day regeneration frequency.
Hardness reduction efficiency: 31,500 gr / 9 lbs salt = 3,500 gr/lb.