Ok, I have a 3en1. Ride my bike to work each day.
On a cold start with the choke pulled back all the way, should she be reving as high as 4k when started ?

She always starts and only take 1.5 turns of the crank. For a few seconds she will rev around 1.5k then jump up to 4k at which time
I drop the choke to 1/2 way and she dies down to below 1k so i have to open the choke again and she again jumps to 4k. After about 2 mins of this
I can close the choke and she is a happy girl idling at 1.5k

Sounds about right but all engines are different.
Always let the fuel pump finish clicking over before you start it, I flick the kill switch off and on again to let the pump cycle again before hitting the starter.

Maybe leave it at high idle for an extra minute