I’m having an immense amount of trouble stretching my pinky out to grab a string in Ben’s Dueling Banjos. Yall have any advice on how to make that runt get off the porch and start huntin?
Pinky Stretch
Ah, the sweet pinky stretch. Got one advice that helped me … Keep practicing 
. Sorry, but don’t know any quick fixes for that. It’s a matter flexibility and a little strength and that takes some time. And of course a good hand position helps, but you will feel strain in the beginning. For good hand position I once got the advice to keep your thumb with the second finger (middle) and that helps me a lot. I tend to leave the thumb behind when moving up the neck but that really makes it impossible to stretch. I still hear this advice regularly (guess college doesn’t result in good memory per se 
) and every time it turns out to be true!
Another advice I got was to take a small part and repeat it endlessly, which I find boring but also terribly effective. So, having the same difficulty as you, I practice this specific lick actually daily with Ben’s tab for bugle call rag. In the middle (2nd break) he plays the same lick and it is a good exercise to loop the first 8 measures of that break, it has the same lick in the first half and a slightly more difficult variety of it in the second half of this. It is measure 27-34 in the PDF. Moreover it also requires stretching from the ring finger playing both this lick at 29/30 and 33/34 and a fret higher in the c&d-chord shapes at 27/28 and 31/32. The eight measures are thus a mini song making it fun and it is full of finger practice. Hang in there!
I don’t know if this will help much and I don’t know if this is good technique but:
I don’t hold the neck like a guitar neck with my thumb doing a lot of support. I hold the neck more like a mandolin neck sitting loosely in the palm of my hand and supported by the crook of my thumb.
When I get into that ‘Cumberland’ position (9-8-9) and do that stretch to the 11th fret, I will often arch the palm of my hand upward so that the neck lies almost flat on my palm and almost fully supported just by my palm. This will give you more strength and support when you do that 11th fret pinky bend.