during the fluidity of combat optimal hand postion depends on your position. If you are unable to draw and end up on the ground a firm icepick grip works well in grappling range. Many grips have use and are situational. What grip do you use if you are bleeding? Guro Dan says blood is like motor oil. What grip is hardest to disarm, what do you do if the other person has a flak jacket? explore the possibilities. check this out, left lead icepick.
http://www.jenbjj.com/floro1.wmv