I tie most of my soft hackles on a mustad 3906, or a 3906b. the 3906b is a 2x shank length of a 3906.

if you normally tie on a 2x shank length, lets say a size 14, you can get the same shank length and the 2x wide gap when compared to the size 14 3906b by tying on a size 12 3906.

hope that makes some sense and I didn't screw up my shank length and hook gap comparisons