When you spread your fingers as far as possible, what kind of angle do you see between thumb and pinkie, and index finger and pinkie? I regularly do stretches and I get about 180 degrees between thumb/pinkie and 120 degrees between index/pinkie.
It's the fascia in my palm and between fingers that I've been stretching. My hands are not gigantic, and I can get 4 frets low on a 34" easily.
Thumb and index, about 90 degres
thumb and pinkie.. I think about 140 to 160 :-(
I do 124 for the low frets. I can do 5-8 1FPF reasonably and am golden from the 7th fret up.
I am realizing now that for the D and G strings I am serious thumb wrapper. I'll cut that stuff out and see if it helps any.