As far as the distributor, you are right about the fact that if it is a tooth off you can rotate the stalk/cap to make up for it. The room for correction when it comes to this is only limited by the advance clearance if it has a vac advance because it will start getting close to or hitting things as it is turned. If this happens then you can either pull the distributor out and turn it another tooth and drop it back in to correct it if you dont have enough room or just switch the wires to the next post on the cap and adjust the timing that way. By switching the wires to different posts, that can get you within a few degrees and then just slightly rotate the stalk/cap to fine tune it.

When it comes to the choke, I think it should be setup to where you can lean/richen the mixture during the period that the motor is choked. It should have rich and lean written on the housing and arrows showing which direction is to richen or which is to lean out. By having the choke set more to the lean side it will not stay on as long because it is already starting out with some air coming in so it obviously doesnt need to stay on as long. If you have it set more the rich side then it will stay on longer which is good for colder places and higher altitudes. In Texas though I would think you would be able to go slightly more to the lean side of the default setting. This of course will make it run a little faster because of the lean condition also.

The carb should also have a fast idle cam to help keep it running when it is cold too and most of them will keep the rpm up around 1200-1500 depending on the setup. Once it has been running for a little while and is a little warmer it should drop off the fast idle down to normal idle speed. Some carbs require you to rev the motor up a little bit for it to "drop off" though. I know mine requires this. You can also do it by hand from the engine compartment as well.