Hi Rich.....when first starting to build LRs {1976}, the type of drill point had to be decided. Having been familiar w/ vertical milling machine cutters, I decided that a flat bottom "point" would cut more independently considering the grain direction, than a normal, angled drill point.
I also have experienced the "happiness" feeling....especially after the 1st RR hole was done.
Did four LRs and the RR hole came out fine on all 4. Later on when visiting Fred Miller, I saw his RR drills and they also were a flat bottom. One advantage of a flat bottom grind is that they're easier to grind correctly and therefore can be sharpened more often.
I agree that the direction of the RR groove is probably more important than the type of drill tip, but grain deflection can sometimes make the drill wander.....especially near the breech.
What type of drill point do you prefer? By the way, after the 4th LR blank was drilled, I began sending the blanks out for the bbl/RR work......Fred