What I want to do is make it so that any given party member can learn up to and NO MORE THAN 60 different skills. If they want to learn new ones, they have to replace old ones. How would I do that?
Well, if your character learn skills through events that add the skill, you could make the event add a point to a variable called, like, "#0001: Hero 1 Skills". A simple fork condition could then check the variable and see if it goes over 60. However, if you have the characters learn it through levels I doubt you can help it. And if they're learning through skill books then I doubt that would work either since it's impossible to "raw-check" the number of skills a character has.
Skill books. Drat. Maybe I could make it throw a switch instead, and have that call a common event.