Cheers Skip, I don't understand how to listen at the holes, you'll have to explain that one. How does doing a hot compression test help you compare the wear of each cylinder?
'listening at the holes', see also, Terms of Endearment".
As briefly as I can make it.....
OK then,..... when you put a bit of air pressure in at the spark plug hole, you can listen at the !. crankcase breather (or timing plug) for air blow past the rings and 2.,listening for air blowing past the valves at the intake and the exhaust ports (or at the silencer if you're not inclined to remove the pipes).
Idealy, and in a newly run-in motor. on a hot comp test, one may expect the readings to be within 1/2 point (or pound) of each other on compression and no leaking of air past the rings or valve seats.
A cold but throughly kicked through motor ( kicked or turned over fast enough to get the oil flowing) will show you differences or an un-balance....
.... say for example's sake, that on a hot check there's no air leaking past anywhere but on a cold check it sounds like a good bit mor air is leaking past some point in one cylinder more than the other..... this might explain un-eveness at startup that goes away once warmed up*.
Compression tests are an excellent diagnostic tool when performed properly. There's a lot of info out there on comp tests.... what they'll do and what they'll don't. Read it up. The knowledge will stand you well.**
Oh! Did I answer your question?
* -vs- chasing your tail over idle/low speed carb settings....... ask me how I know..... no.... don't.....
** if you do go looking for the knowledge, you might give some viewing time to how comp tests are done on small, 4-6 cyl. aircraft engines. There are useful pointers that may help you beyond what a motorcycle vid would show.