Thinking about my 30-30AI, the neck area expands about 2 thousandths from loaded to after firing. Is that enough?

What should it be in most bottle-neck cartridges to prevent pressure problems? If accuracy is good and no pressure signs occur, should I assume it's OK.

My custom 30 herrett barrel had a tight chamber. The rounds chambered easy but after firing, the neck was basically the same. Ran into poor accuracy and pressure spikes. After neck turning the brass, the problem went away and accuracy was good.

Yes, that is enough.
just make sure you keep everything clean.

I had the same problem w/ a 7-08 and 6.5T/CU. After a little turning everything was fine.

I'd also say you are fine for the 30-30AI....002" after firing is plenty good since the brass will have fully expanded and sprung back when you took the measurement.

My .222RMI has a .248" chamber neck and I cut my cases to .2455" when loaded. This is on the tight side but it does not display any early pressure signs or spikes.