I tried that on my Triumph. Belts all different. Took 2 off leaving just the 1 belt. Made no difference.Will have to test mine with a tub of water and see if it is anything like yours.
Regarding the belts, supposedly if you mark across them with chalk or similar then run a while then stop and rotate by hand to find the marks and see if they still align, if they do the belts match, never tried myself.