Just be aware that high FC can throw off the pH test, as to sequence I would test most often the thing that tends to drift most on your pool, experience will tell you what that is, but it will most likely be FC or pH depending on your pool, if you have an SWG, etc. For example on my pool the pH is usually very stable so I only test it once ever couple of weeks unless I have recently been using other chemicals that have acidic side effects like dichlor, trichlor or CYA, by contrast someone that buys acid (or Borax) for pH adjustment on a regular basis instead of my once or twice per year might want to test more often.
