Does the S&S TB have a high idle air bleed? These typically will bump the idle rpms up 200 to 300 rpms on cold start. My '09 Harley does this, but it's a throttle by wire setup. As I think about it, cars that were before TBW setups, still had the high idle bump via the air bleed port.
On my Willys with it's blown 392 hemi, I had two 700HP Holley carbs without chokes. I would turn on the fuel pump and just pump a few times, then it would fire up. If I kept it at around 2k rpms for a couple minutes, then it was good to go.
Anything like the M3W needs a bump in rpms at cold start. Even late model bikes with carbs, the choke/enrichment circuit would pop the butterfly open a bit during the startup.
I agree about the battery though. Even though it's not an issue now, it could be later on. In cold weather batteries start at a voltage point below when warm, so you're turning a cold motor and with lower than normal voltage.
I guess if you're in the need to keep your baby outside when cold and it does not have an idle air bleed, I think it would fairly easy to add a slight bump on the outside TB butterfly cable assembly with an auxiliary cable. Lots of old cars and tractors had a high idle separate cable that you could pull out to bump the idle. For tractors it might have been used to run a PTO at higher than idle rpms.
On my old '76 Harley with a choke, I have a setscrew under the throttle grip that I tighten up and it sets the grip at any rpms I lock it at.
Sorry for rambling again guys. I'll shut up for now...
