John, I have played with the concept of using a sling for steadying the rifle mounted with the barrel band stud.
I found that with the sling held to the fore end with a good grip and a bit of slack ahead of the hand I could hold it tight enough to easily give a hasty sling help to getting a steadier shot off.
The other good thing is that it is not determined by the sling length as is the usual fore end mounted sling stud as with a longer sling length to have the rifle ride lower ion the shoulder you can simply grip the sling further back and bring it forward to the forend till there is enough tension round the off side upper arm to give the steadying effect.

Looking forward to seeing the rifle as the blank shows excellent promise. Any decission on the other blank you got. You do know that you will have to do a 318WR soooner or later so you may as well do it now if the second blank is aas good as you indicated.

Von Gruff.