Conditional Fields, Dropdowns & Class Enrollment / Waitlisting

I am considering purchasing Gravity Forms but need to make sure the following in possible

there will be a drop down titled: "Choose Your Class"
each class will have 50 slots; Class A and ClassB

In a perfect world I would have the following:

How many people do you want to enroll: {number}

Which class do you want to enroll in: {ClassA, ClassB} (however, if the enrollment already for ClassA + {number} > 50; then display the options {ClassA Waitlist, ClassB} as the options instead

*** SO I need 2 things. I need the form to know 1) how many people already selected ClassA to enroll in and 2) if the current number enrolled plus this new {number} exceeds 50 and if so display ClassA Waitlist

Not sure if this conditional logic is too complex

So - if I wanted to do this how much support would I have? also - would I have issues when Gravity forms is updated?

So I bought the plugin ... where would you point me first to figure out this functionality?