Class override each other

I have been making a 1v1 map where I have options to choose ur max health from 160 to 200.
I also have another option where you can select your gravity to low, medium or high. The problem is, when somebody selects max health (example 160) and also the gravity (example low), the freshly selected class overrides the previous class (example, the gravity becomes low but the previously selected class gets cancelled and the health goes back to default, which is 200).

is there a way i can give players both gravity class and health class they want?
if its not possible in creative, then is that atleast possible in verse?