as a secondary question to my question about bullet selection; what about grease/lube grooves? 
  There appear to be 3 styles, square cut, round, and beveled. (plus the mini-groove "tumble lube" style)
  It seemeth to me that given equal lube carrying capacity there is not a lot of differences, except that the round or beveled ones might drop free of a mold easier and the square cut ones might retain their lube a little better in storage.  what else?  am I missing something?
  Some of the more recent mold designs (I am thinking of some of the B&D molds specifically) feature a LOT less lube carrying capacity than "traditional" designs.  
I'm wondering about that too?  Tre the multi-groove high-lube capacity bullets a carry over from the BP and transitional smokeless powder days.  Is the old "what was good enough for HarryP" thing still influencing mold design?
I know that both Jim and Barry were shooting their bullets at significantly higher velocities that we normally associate with our plain-based cast bullet loads, without leading as far as I know, and with exemplary results, both at the range in matches and at the experimental bench. 
I know some other top shooters are also using B&D bullets and when they shoot it sounds like they are also using higher velocities----I don't know if they are the reduced lube designs or not.

Is it modern bullet design, and/or,  more efficient updated lubes that are making this work?

If your particular lube works quite well, fewer or shallower grooves might be used. If your lube is marginal, more grooves might be necessary.

I ran across this note which I believe I obtained from some info provided by Corbin...
"Grease grooves that have a radius at their bottom will collapse, and may cause a shortening of the overall length with reduction of ballistic coefficient. Grooves that are square will tend to expand outward, possibly forcing lubrication to the barrel’s bore surface."

A lot of the answer depends on where you are. Hotter dryer climates demand more lube. D.W. for you I would use 3 or 4 Grooves about .015 deep with on a radius of about .040 let them be as wide as they are. 

40 Rod