One of the issue with expanding the size of your loops with loops or NOPs is that you run out of music for your song.
You should be able to make a single loop so everything.
I've not seen a easy way to do this but 6502 is not my best assembly.
Anyway the way I thought that might work is to have a value on page zero that has the number 100 speas into the two locations ( I forget if it is 00 first or 1 first for an address on the 6502 )
Anyway, at the beginning of each loop do a EOR of 3 on the location with the 1 in it wan write it back then use that location for an indirect operation. Each time it will change from 100 to 200 and back.