I generally copy my original Howard Hill bow (his own), which has all of the lams forward of the riser. Only the belly glass goes up the fades. He felt that the stack worked better together than split. I do split it in two situations... if the belly lams have fantastic grain I want showing rather than hidden, or if the weight goes over 50 pounds, in which case I will put at least one lam on the belly. Fortunately, I rarely build that high a weight. Note that this is on traditional straight longbows. What the situation would be on a recurve or RD I have no idea.