Payroll categories for different levels and ages - how to set up easily?

We have over 100 different payroll categories in our award, and the wage amount for every single one changes each new FY. All of them are based off 4 original wage rates, and then the others are all a percentage amount of these. 

E.g. We have permenant level 1 adult as a base, and then 6 different age categories and then each of these has 7 different time categories. Not to mention the same again in casual wage categories.

How would it be best to enter this? Currently every single payroll category has a different monetary value, but I'm wondering if it would be better to have them as a % of the "permenant level 1 adult" category? 

E.g. Perm level 1 adult is 100%, then Sat is set at 125%, Sun set at 150%, 17yo set at 60% etc.

My three main qs - is this the best way to go about it?

If yes, how would I then enter the junior weekends etc (such as 17yo Sat, which would be 125% of the 60% of an adult)
And also, how do I also factor in those paid above award?

I hope this makes sense! Thank you!