By the book, warm idle is 1000 +/- 50.
The idle mixture is affected by the pilot jets. Changing the mains won't make any noticable difference. BUT, the idle mix will need occasional fine tuning to allow for seasonal changes, traveling to a different altitude, etc.
I have had good results adjusting the mixture for best idle speed. As the engine speeds up during adjustment, slow it back down to keep it running only on the idle portd.
Anything that changes the amount of airflow is likely to change the mixture and require adjutment.
If you can, it's a good idea to get some kind of carb balancing guage. Even if you don't change anything, this will drift over time.
