Welcome to the forum, Zaneyboi. Just to be sure we're talking the same on ratios, an AFR of 14.7 to 1 air to fuel is the stoichiometric ratio for maximum efficiency - a nice target number for highway cruise, but likely never seen at idle or acceleration. As we go "rich" the amount of air to fuel drops - the 14.7 goes lower. As we go "lean" we're pushing more air for each volume of fuel, and the 14.7 goes higher. When you say that in less than a minute your AFR goes to around 12:1 you're getting richer than you were on initial start which doesn't make sense. Even in Alabama on a cold start your choke is set, so I'd expect an AFR of more like 10.5 or 11 to 1, then after a minute or less the choke plate is opening and the AFR would bump to maybe 12 to 1.

On your idle stop you need to adjust your idle air screws to maximum vacuum, right? The old school approach was to close one until RPM dropped, open until RPM dropped, and set halfway between the two spots but vacuum is better. From you saying it goes "...straight dead lean" I'm wondering if maybe you went the wrong way on tweaking the primary jets?

I've never messed with a Street Demon carb, so I apologize if I'm leading you down a rabbit hole. Maybe one of the guys will jump in and help out a bit, but glad to have you here!