Heavy Jatoba/Hickory board bow?

[AKmud]

What I have so far....

I'm planning a heavy board bow (~75#) for a friend and am trying to use a Jatoba board I have been neglecting for about 6 months.  I have the Jatoba cut to 2"x3/4" by 74" at this point and just glued up 1/8" hickory backing.  Next step is obviously to lay out the bow.  I was wondering what design would be the best to get to my target weight with this wood?  I was thinking possibly a diamond bow and keeping the length around 70"? 

I'd like to heat in some reflex but is it too late since I already have the backing glued up? 

Any ideas or recommendations? 

[sulphur]

Jatoba is much like ipe.  not as dense though.  you'll be surprised at how much wood u don't use.  for such a heavy bow the 70" should be good.  don't worry about not heating in some reflex, jatoba doesn't bend well with steam or heat.  i have noticed that time and pressure do a decent job though.  if you set it in your jig and clamp a little at a time over a whole month it bends.

[AKmud]

Thanks Sulphur.

I am laying out the bow today and am wondering if I can get by with a narrow (say 1 1/4") handle down to 3/8" tips and still get my weight (board is 3/4" jatoba and 1/8" hickory)?  Will those dimensions be too thick for the Jatoba?  Do I need to go wider/thinner? 

I haven't worked with this wood before so this is new territory for me. 

Thanks in advance!