Dave,
I was not picking on you about the jet drilling, just pointing out that we defer to your obvious "try it and see if it works" attitude.
As for your current problem. There are only two simple reasons for needing choke on a warm engine. One is too much air, such as a manifold leak. The other is too little gas, as in water or crud in the carburetor. Assuming, of course that the mixture was ok to begin with.
There are more complex reasons such as crank seal leaks but they are less common.
You seem to have the exhaust off a lot, you can look in through the port and see if the piston is scuffed or the rings siezed.
Keep us posted,
Ron