Yes more or less rennet through out the year , that is the advantage that daily making gives the pro .
I use 19 drops for 3 gallons raw milk when the milk is at it's best , and 17 when is is less so , that gives me about. 15 minute floc. Which is optimal .
Still have yet to nail down the exact amount for the commercial pasteurized stuff.
If and when I have had curd ph dropping faster than I like I have either taken out whey and added water to the cut curds , or lowered the temp during molding , depending on type of cheese and when things started to go down hill too fast .
In your case. Would have gone for the whey / water , and then if that was not enough a little lower temps