Hi Andy, What sort of electronic ignition and will the bike run? Static timing is usually OK to get you going and then fine tune it by running it up a hill steep enough for it to top out at about seventy. Then adjust a tiny bit and try again aiming for the adjustment that gives you the highest speed. Obviously watching out for detonation.
As far as the 23 tooth sprocket is concerned. I would leave that until the bike is running well and you've got used to it. Then adjust the gearing to suit your riding style. In my opinion trying to pull too high gearing is more suited to Big Twins.
