Just tried Roto 77 Monel Flats on my Jazz... Like! Tried La Bellas on it last week and they didn't really work. But they sound phenomenal on a P... erm... that's it.
Are they still rough feeling and slightly clanky sounding for flats? I had a couple of sets in the 90s when I was starting out, and that's my abiding memory of them.
The silks are tatty (being used) but the strings are smooth. They are slightly more toppy than La Bellas but still round and warm. Good flats for a Jazz.