Rafter pullups training questions

[Adam Juncker]

I've always had this goal in the back of my mind and my latest frustration with pinch is making me want to pursue it. 

I've really hit a wall with pinch the past few months and have decided to hit more narrow <2" pinch for a while. 

With that, I've always wanted to do rafter pullups.  I'll be doing these in my basement, so they will actually he floor joist pullups but that's not important. 

I'm weighing around 180 right now. Can get 12-15 strict full-lockout chinups when warmed up. But my pinch really sucks.  With a 2" climbers pinch I got 80lbs to about 6" so I've got a ways to go there. 

I've read of a guy standing on a bathroom scale to determine how much pressure he was able to pull, and I've already tried pull up assistance bands (not good when you slip).

I wondering if any have have trained for these and if anyone knows of good ways to progress.
 

I see some doing the pullups on one rafter, and others doing it with 2. Using 2 rafters and and neutral grip seems harder to me but I'm open to any advice.  

[Climber028]

Two rafters is much much easier, since you can squeeze your chest and get extra force on the outside of the rafters. With 80lbs on the climbers pinch it seems like you're already pretty close, have you attempted just a hang yet? The only practical advice I have is that it's easier to hang with a bent arm, and that the pull gets easier if you bring your elbows closer together.