Timberline,
I think you've gotten the info on just who Alexander Henry was;the info on the purpose/function of the groove is more likely the shooting sticks idea rather than for a toe hold. I have never heard of another reason that I have confidence in.
The AH style has been around on the No.1 since the begining, as 3 of the 7 Prototypes were so stocked. In the first Advertisement, it was refered to "a slender sporting type".
I think you can see where Ruger got it from the photograph on page 70 of the Wilson book "RUGER & HIS GUNS". If you have any interest in Rugers at all, this is a must book for your Library.
Congratulations on your acquisition of one of the 9.3x74R in the 1S. I predict they will turn out to be a fairly low production caliber. To support your Ruger No.1 interest, you should get a copy of the book by J. D. Clayton-"RUGER No.1". Send me a PM and I can help you with either of these books, if you have an interest.
I have to admit it took me a long time to warm to the Alex Henry forearm style; now it is my favorite over the semi-beavertail. Of course some of the Custom jobs with a shorter, slimmer beavertail style are rather nice.
