How high is the safest for FC to go?

This is a vinyl, above-ground pool (about 5000 gallons) that will be covered (but with a vent) while we are away on vacation for a week. We will be adding bleach before we go, and someone will (hopefully) be stopping by midweek (probably 3-4 days later) to add more.
What is the highest FC level we can aim for and still be safe for our pool? There won't be any swimmers during this time.
We just added about 4 ounces of polyquat 60 to the pool.
Our CYA is about 42 and our pH is a bit on the higher side (about 7.8 or so). Our calcium hardness is in acceptable level range (can't remember the specific number, but nowhere near too high).
Thanks for any advice.

I wouldn't take it any higher than 15. Remember the Polyquat 60% is gonna drop your cl level so you'll have to raise it back up after you add it.