Here is what I'm using, M4 with the COG in the dead center gives me a 20 yard fade/slice.
M4 D type way over in the heel side COG gives me a straight ball.
And, I don't care what Tom Wishon or Tinker or Tait or anyone says. 🙂
Because it's real and it's spectacular.
I can fight with the regular M4, adjusting my grip and such, and if I really work hard I can hit a straight ball. And I hit a lot of nice little fades. But the average is probably 20 yards with what I consider a normal grip and swing.
The D type is super straight with the same swing, and the EXACT same shaft. Not another one of the same model, the exact same shaft, swapped between heads.