Find thee straightest, cleanest 12-14" diameter chunk you can get seven feet long. Be sure the bark is running up and down and not spiraling up the tree. Take that perfect log home and quarter it with two wedges and a sledge. Start on the skinny end always. Split those quarters again and seal the ends with shellac, glue, deck sealer, old paint or whatever you got. Give them a SUPER dousing of insecticide completely. Store them flat somewhere that doesnt get extremely hot when the sun comes out or in the summer...i.e garage attic or barn loft. Garage floors work great, semi dry basements to. Leave them sit just like that for no less than 2 years. Spray them once every six months with insecticide. Borers will eat them over night. In my opinion that is the best way to make a great bow as you want. You can make just A bow in much less time with all kinds of shortcuts. Its your call there. If it means that much to you and you want it to last, I say do it right. Thats my .02 cents, good luck and have fun! You have two years to study this forum!