Osage is rare around here, too. Only made a few bows from it, but
If you are familiar with laminated bows and know about power lams and all that, you have plenty enough for 2 bows there. Very strong woods like osage and massaranduba take very little thickness on a R/D profile to get good draw weight. I have made hunting weight, 70" long BBO's with 3/8" of osage and 3/16" of bamboo, again, with a powerlam.
Early on it worried me, and i remember spoiling some decent osage bought off ebay by putting 1/8" bamboo, about 3/16" of boo flooring, and 3/8" of osage. i could stand on that thing between uprights and bounce when it first came off the form. I ended up withMAAYBE 1/8" of bamboo in the thinnest places and it took a lot of set.
The ONE caution I have is that I have had some very bad quarter and rift sawn tropicals and osage before, and it's hard to see. Several backed bows in a row died on me, because the boards came thin, and I couldn't see the grain on the sides. It turned out the radial grain went back to front at about 15 degrees, and under strain, the belly lam would fracture by slipping, separating along the grain and raising a lip, kind of like a spalt or spall (sp?) fracture. Sio, look at what is really there before you saw it.