The 3 with damage use are Atlas 520 sprockets, the nice un-used one is 530 Commando version I'll be using next time out on Ms Peel, which is the bike that gave me the most fun and learning curves.
I wouldn't mind a 19T in a city but its too much rpm for 70 mph above sustained speed to enjoy. Best all around for normal power Combat is 20T, might even be faster acceleration by taking some advantage of the torque instead of delay to rev.
But its just less hectic to cruise around on, allowed 80 mph freeway travel a bit under 5000 rpm and still plenty of pull and some caution to snick 2nd w/o tire spin hesitation in get go. On Ms Peel in her prime power set up 21T was better for evertthing but rather slow creeping home at night on loose rutted drive, too fast in 2nd gear to keep bright beam brigth, yet too much rpm pleasure in 1st to keep some momentum going across the slight slip/slides that easy drop ya at slower pace.
21T with taller 2nd gear allowed 35-85 mph chicane dicing in best power band under red line risk zone. With rear link that more than enough to out dice any other bike supermotards included if you got the skill and balls for it - mine were handed back to me smashed to smithereens by THE Gravel lesions. So I'm an enunich on it forever more. BTW most super motards at any speed over 40 mph ain't got the power to slide rear into turns so mostly they are on rear brake to keep from high sides tll aimed around enough to use power to help upright again. Ms Peel in 1st and 2nd could power spin the rear out at will over 65 mph if leaned enough not to hi side too much on the flip back on hook up in right direction to hit full power again. That's the only time I let her run to 90 mph/2nd, comming out a 10 mph turn at 65 and next bluff face 10's of yards away and could see no oncomming traffic in road way over head. I had to brake to 55 before the next fling. This was 1st try of the triple linkage and will never do it again as too dangerous into blinds and was the finish up of a bunch of prior 10 mph turns to test lean then front and rear traction limits to know.
My race tired SV650 would lose its grip and jutter like crazy at 35-40 mph in same section, so never press it no more either for so little to gain so close to crashing.
With the full rod set up you don't have to worry much about entry speed if staying in two tire traction normal leaned counter steering. which is still rather faster than moderns can take it on fat leaned tires. Fork mods I did are part of the miracle handling of Peel, as the chicane was over broken patched and ice heaved pavement on wagon trail climbing face of plateau. Fork end blur out of focus i found but no effect on handling feel and security, thank goodness.
So experiment till you are squealing in pleasure of road orgasms. If ya live that long being a motorcycler.