Roughly speaking, one sets the CYA level according to the amount of sunlight protection they need, though usually not too high (with SWG pools, 80 ppm is OK if the FC is set at 4 ppm or higher). Then with the CYA level, this determines your FC target.

You set your TA appropriately for your source of chlorine. For hypochlorite sources, you set your TA on the low side, usually around 80 ppm but sometimes lower if the pH tends to rise. The pH target is usually around 7.5, but for SWG pools where the pH tends to rise it could be 7.7. After all of these are set, then you add enough calcium to have the CH high enough to have the saturation index close to zero. So in an SWG pool, with its higher salt level and a tendency for the pH to rise, one may have a lower TA and a higher CH than in non-SWG pools.

Richard