Keep in mind that bore diameters change from gun to gun, so the overall choke restrictions are not the same.
My bore diameter on my 12ga Benelli is 0.728" and on my Berretta is 0.7305"
Modified is what works best on Benelli and a IC on Berretta.
At the beginning of season I use 2.75", 1 1/8 #B @ 1475fps (RSI#64) or 3", 1 1/8 #1@ 1590fps (RSI#83)
at the end of the season I use 3" loads 1 1/8 #B or BB @ 1590fps (RSI#83)
Finding the best combination load + pattern requires some shooting on paper.
A good page to analyze your patterns is that of Dr Jones
http://www.shotgun-insight.com
The page has not been updated in years and you need an old PC and browser (with Jawa enabled) to make it work.