Is there a real advantage of 4 lams over 2?
Yes, usually. Inconsistencies/weaknesses within the laminations are better compensated with more, thinner laminations.
Thanks. Thought it had to do with speed and cast.
thinner lams are better for going up riser ramps and recurves with aggressive "hooks" like some of the static designs. there are 4 amberboo lams and two 020 veneers in this 42# bow, the 2 running up the belly ramp are both 060. (http://i596.photobucket.com/albums/tt46/Robertfishes/bubingariser3-13_zpse451fdad.jpg) (http://s596.photobucket.com/user/Robertfishes/media/bubingariser3-13_zpse451fdad.jpg.html)
I agree more lams are better. I can't help but think that the added glue aids in this...