IF you have a vinyl or fiberglass pool, you don't need to be concerned much at all with CH or CSI. You can just maintain your pH between 7.2 and 8.0 and you'll be fine. Your TA will come down each time you add acid. If your TA gets below 60, add a little baking soda. Trying to keep it 80 or 100 as an arbitrary number doesn't make sense. Keep it at a level that limits how fast your pH rises since TA and pH are very closely linked.
If your pool is plaster, then pay attention to the total number, CSI when all your levels are taken into account. Use the Pool Math link above to input all your numbers and give your CSI. pH has a drastic effect on CSI so most CH and TA levels are manageable to keep a neutral CSI, within reason.
As has been said, the CYA/Chlorine ratio is a fixed one so your minimum FC is entirely determined by your CYA level.
The methods here might not fit on the back of a napkin to cover all the nuances, but it's fairly simple once put into practice and transfers from pool to pool as documented by the thousands of satisfied users on this site.
Spend some more time in Pool School, especially the ABCs and CYA/Chlorine link in my signature.
Updating your signature with your pool details will help us give you better, more tailored advice.