Art, my thumbs muscle does rest on the grip, well about 2/3 of it does.  My elbow is bend out, so that probably means it's not a straight grip.  (I'm just learning these terms)  I just shoot what feels natural.  

  The rest on my hickory bow is 1 1/2 above center.  It seem good.  But, then what do I know.  So I"m thinking 1 1/4 to 1 1/2 about center? ? ? ?
Good new for SILLY me!  I've been looking at these billets.  I know they came for the same log, but the rings just weren't matching up.  hmm Where's the rest of this log?  Well, 2 more billets were hiding in the shed.  And, they look as good if not better than billet #1.  This means I don't have to be so exact with splitting and laying out this stave to try to get 2 billets out of it.  I only need to get one billet from this one. shooo what a relief!
I've actuall removed the sapwood and rough square billet #4 already.  I used a foe.  I did nick the first ring a little bit which I thorough expect I would.  But, the second ring is just as good.  So, no problem there.  As soon as I have a bit of lunch, I'm going to remove the sapwood and rough square billet #1.  I'll post pics this evening.
Thanks guys for all your help and support.
Dave