Main venting question

Dave0176

I got about 25' of 2 -1/2" main, then it's reduced down to 2" for the remaining distance of about 35'
How much venting is required for that run, there is only one Gorton No. 1 at the drip elbow tapped for 3/8 pipe??

Bio

I would do two gortons #2

Dave0176

Forgot to add there is another 25' of 1-1/4" dry return with one Gorton No.1 on the vertical drip. Definitely doesn't seem like enough venting? Thinking maybe three No.2
The other return only returns two run outs and sized with one inch pipe and has one No.1 on its vertical drip.