I agree with Greg on how to size the moor loads.
I will add that the GFCI main breaker would concern me if it was my job.
With all the equipment you will have connected to the GFCI it is my opinion the cumulative leakage current will cause nuisance tripping of the GFCI main.
In my opinion it would be a more reliable installation to provide GFCI protection for each branch circuit that requires it and replace the 60 amp GFCI main with a standard 60 amp breaker.
Bob
