Contact Jim Thorne
Go To: buildyourownbow.com
I think Jim sells a TD bow plan that looks pretty nice when completed..
I think the advice given above is how most guys go about it.. A huge part of the adventure is looking at bow features you like, thinking it through, and tinkering with your own design.. But it sure is a big help, to build a proven design for your first attempt..
Good riser woods are all about your taste, as long as its a hardwood, without grain runout..
Bubinga, Zebra, Bocote, Shedua, Wenge, Osage, are examples of common riser woods that dont break the bank to acquire.. For a recurve you'll want to select 8/4 lumber... The layering in the riser, you ask about is largely decorative, and would be done to create your own style, and appearance. The "center beam" in your last picture is a way bowyers use thinner lumber to build up a block wide enough to build on. This fashion can also be used to create a stiffer riser block, eliminate risk of grain runout (split), etc..
Jump in and have fun..