All adjustment, choke pull-off unload angle, fast idle speed, idle speed, idle mixture, etc, etc, require custom settings beyond what information will be supplied in any written instructions. The factory settings were there to get you close right off the bench, but further fine tuning will be required if you want perfect setting and flawless operation in all areas.
This fact is further compounded by many things, including removing factory emission control parts, engine modifications, differences in fuel blends, etc. It's also pretty rare these days to see anything that is completely "stock". Many of these vehicles are a half century old or close to it, and many changes will have been made to the engine and associated parts over the years.
When adjusting the choke and related parts for instant cold starts w/o stalling out, it may take several attempts from dead cold to warmed up to find the perfect settings. One has to work pretty fast as the engine and intake heat up pretty quickly unless someone has blocked off the heat crossovers (bad idea for most set-ups).
Also most older carbs require bending of linkages in lieu of just turning the choke dial or adjusting the angle of the choke flap with the screw on the pull-off.
Also interesting that as "dated" as divorced choke set-ups are that were used on early models they work flawlessly once one finds the most ideal settings.
For the most part I use and prefer later carburetors converted to electric choke on my own engines, but have owned a number of earlier vehicles with electric choke set-ups and they never gave any issues and worked fine once I found the most ideal settings for them......Cliff