Yes pieces that are made of more than one kind of wood are glued up in 1 or more stages. Our core design is a closed system and keeps the wood/glue out of the air path but we only use glues that are FDA approved for food contact (like cutting boards, utensils, etc) as a matter of principle. Yes you can totally use bison, lizard or other bottom types of your choosing. You can provide your own or we can source it for you. We usually keep about 20 different leathers in stock including some bison but I think we might have run out on a recent project.. but no worries we can always get more. Also, not sure if you saw my edited first post but there's a discount code that provides FC members with upgraded free shipping and some other surprise goodies! I also touched briefly on our trade-in/upgrade program which people always like. Last but not least for everyone purchasing a vape before December 31st we will be having a New Years drawing for a totally free, fully commissioned piece.