Correct. FC of up to 40% of CYA is entirely safe to swim.
You will have roughly 1 person per 1000 gallons of water. That magic # is the only time my pool went cloudy in 9 years with more parties than i can count. It took 35 swimmers for me to hit that threshold, and it was a rager.
Now, to be clear, the cloudy wasn't from low FC, it was sweat, body oils, sunblock, residual laundry detergent from all those suits, etc. But that all needed FC and lots of filter time. So you are going to want to start at or near SLAM for your best chance. Even if the swimmers make it a bit cloudy, you will be sanitary. Run the pump throughout and it will likely need a day to clear if it does go cloudy. Thats just the filter doing its thing.
Toss 3 or 6 tennis balls in the pool. The hair sucks up alot of the oils floating on the surface. You can buy name brand 'scum balls', or use the Po' mans version.
Also, there are two kinds of kids. Those who pee in the pool, and liars. Juice the FC.