Ted
I enclosed a photo of the plane I've been using for several years. It is the "low cost" stanley model low angle block plane which has been modified by grinding the sole with a belt sander. I removed about 1/8" on the side-edges and left the middle untouched. I made a nice smooth curve from side to side onl.

I have no rocker. there are times when a little rocker might be useful while planing the inside of a hull, but for the most part I think I need the support of the long straight sole for smooth cutting.

: Eric,

: I have an old block plane that I want to modify for the same purposes. What
: radius should I aim for? Do you also put a little rocker into the sole or
: do you leave it straight?

: Thanks, Ted