Questions about building tri lam wood bows

[Flinttim]

I have it in my head to make a tri lam or even quad lam bow next Winter and have questions. BBOs HBOs and selfbows are my experience up to now. I have plenty of osage lumber and am thinking either bamboo back with osage core and bamboo belly and some accent wood thrown in or  hickory back , osage core and hickory belly. Maybe do the hickory first as a test run for practicing the glue ups.
 Anyway, the questions. Is tillering down mostly by mathematics , ie: figuring the tapers of the woods and the width of the limbs to achieve weight and draw length ? I know it would be on one with a bamboo belly but on one with a hickory belly can you get some tiller wiggle room by scraping the belly ?
 I would appreciate some feedback from anyone who has made such a bow,like dimensions of the wood used, type of wood , etc etc. I figure if those numbers are out there it would be better than me trying to reinvent the wheel. I looked around the TradGang site for a build along on this type of bow but did not see one.

[wingnut]

Tim,

You can tiller some.  However the best bows will come when the math is right and very little tillering is required.  Pick up a copy of TBB4, our chapter has a build along that covers this bow pretty well.

Mike

[Pat B.]

Mike, where can one buy TBB4?

I'll look at 3R's.

[razorsharptokill]

Mike has them too. Got mine at OJAM.

[Flinttim]

Thanks Mike, I've been meaning to get that new edition. Got to keep my collection up to date.