Main Vent sizing

MikeyB

I'm looking to relace an end of main vent on one main that is approx 40' long of 2" and then reduces to 4' of 1 1/4" then bull heads a tee that connects to the wet return and a section of cast iron baseboard, there is a Gorton vent in place now (located on the 1 1/4" upstream of the bullheaded tee) that was bushed from 3/4" to 3/8", looks like i have to move about 0.96cf of both the 2" and 1 1/4" pipe. Then there is another main that is approx 25' of 2" main then reduces to 12' of 1" pipe for a dry return, there is no vent on this main, I will have to install a vent on the 1" dry return before it drips down. in the 2" main it loks like I have to move about .575 cf out of the new air vent I install in the 1" dry return. I thinking of maybe installing 2 Gorton #1's on the longer main, and maybe one Gorton #1 on the shorter main, Do you guys think these choices sound good, or should i go with another brand/size..Thanks guys