Arachnid, I still would like to know the thickness of the ipé board. It's apparently over 70" in length, 1 5/8" wide and what thickness? You may be able to get two bows out of that board.
There is obvious grain run off, but not terrible enough to render the end useless. I think I'd personally cut the board to 66" for now. After the glue-up, the ends probably need to be trimmed so you'll end up with 65" or so. I'd make it a bendy handle, but that is personal.
One powerlam (about 14" length, very gradual taper from zero to 1/8" thickness in the centre) will really stiffen the handle of the bow. If you would add three or even two lams of 1/8", you will have a stiff handle. So, do you want a stiff handle or a bendy handle?
There will be some thickness taper, but that needs to be determined during tillering. For the glue up, start with about ˝" of ipé. Floor tillering probably requires ˝" total thickness (bamboo included), tapering to 7/16" (total thickness again, ipé+bamboo). Most tillering will be done in the area from mid limb out to the tips, where the thickness will end up to be lowest. But you shouldn't worry so much about the thickness, since that is determined during tillering and is different for every bow. You just need a figure to get you started with the glue up, and that figure is ˝" ipé (and max 1/8" bamboo).
