Have made the switch from 8125G to 8190. So far no noticeable changes in sight marks but my bow has become much more quieter. Not sure if the number of strands has anything to do with it. Was shooting 16 Strand 8125G, now 21 Strand 8190.
Stop when you get to 21 strands (round the posts 10.5 times) .
Of course, some people like to tie the ends together, which would make that impossible (except by cutting a strand out afterwards...). But it's not actually necessary, as the serving ties everything in place.
It's maybe slightly more fiddly doing an odd number of strands, but only slightly.