I was just thinking the same thing LOL. If I were you I'd get a probe kit and probe each snake to confirm. It's much easier and there's not much chance of messing it up.
https://www.ebay.com/itm/6pc-Snake-P...kAAOSw1JVaJIwd
https://www.ebay.com/itm/K-Y-KY-Jell...gAAMXQCgpRyLHJ
Just choose the right size probe, lube it with KY jelly, and slowly and gently insert into the vent. Then wait for a few seconds for the snake to relax so it goes all the way in, don't push it hard at all. Then you can count the subcautal scales and tell if it's a male or female, easy peasy. It's best to watch a few YouTube videos before you do it. I recently bought a collection of virgin females ready to breed (10 snakes) and they guy raised them up for three years. He never probed them and sure enough, one was a male. I didn't find out until I paired it up with another male and heard them thrashing around in the tub LOL.