Ron, Barbie,
My reason for liking .067 isn't because I think it may be faster. It's because I'm a fan of clean. I can get a pipe cleaner through it.
I'm not sure how fast the flame spread is from a igniting pan, but it may travel through various holes at the same speed. (To my knowledge no one has looked into this.) There may be a greater amount traveling through a larger diameter, but likely at the same speed. (This is unproven speculation.) BTW a Russian test showed a flame front in BP that was supersonic. I don't know if this was uniform throughout their tests.
Regards,
Pletch