Usually, nobody says let your FC drop below 5ppm unless you're dealing with a metals issue.

Are you aware that Dichlor adds lots of stabilizer/CYA, and so does Trichlor, and that Trichlor is also very acidic? Liquid chlorine/bleach adds nothing but chlorine so it's always safe to use.

We generally do NOT recommend phosphate testing because, except in peculiar cases, it's USELESS.

However, it is your pool and the ultimate responsibility for it is yours. We can only make suggestions.