Sometimes I make a fully laminated bamboo core, and I find that when you add the dense hardwood along the sides , the result is a bow which takes less set and is better in performance. Especially in longer bows like you are wanting to make. I believe that Japanese bowmakers of old, discovered the same thing, otherwise they would have used an all laminated bamboo core. There are so many combinations of core materials and the way they are oriented, that your imagination is the only limit. Using 5 bamboo and 2 wood in the core will give a nice smooth draw, and using 3 lams of bamboo and wood along the sides will yield a stiffer draw. When I make a bow for someone I consider the person using the bow and how they want it to perform. Ex. hunting or target shooting or long distance shooting etc. Shooting heavy arrows or light wt. arrows. Long draw or shorter draw, on so on. Then I choose the bamboo for the core and the wood matched with it . It's the core which is the engine for these bows, and that's where the speed and cast come from. Of course there are other factors influencing a bows performance.So how are you getting along so far?