What is your air temperature? The colder the air the more difficult the startup. Offhand I don't remember what my mains are but my slo is 27.5. Your airscrew sounds about right but you need your engine warmed up and idling to do a fine adjustment.
Is your choke cable properly installed? No choke, no start.
Is your carburetor pump working and squirting fuel? I pump the throttle several times, on each try, to get some liquid fuel in the intake to get the bike to fire. If it doesn't start after a couple of seconds then I stop and twist the throttle several times again and repeat. When the bike is fully warmed up it starts easily. Usually no choke but sometime a throttle twist or two.
Trying to start inside the garage, so warm temperature.
Can't figure out any other problem than carburetor.
Took it off and tomorrow rip it out.
Let's see what happens...