I've used TBIII with hickory backed ipe with good results. Don't make your bow too wide. My first hickory backed ipe was 2" wide and when all was said and done the hickory backing was thicker than the ipe belly wood. 1 1/4" or even less should be good enough for a bow 62" to 66" long for a 28" draw. You could easily get 60# out of it. Like osage, it doesn't take much ipe to make a good bow.
With TB glues, you want flat, smooth glue surfaces(no toothing) and enough pressure to get a good glue line without squeezing all the glue out. I use spring clamps for glue up but some use a wrap of inner tube cut into strips. This seems to give almost perfect gluing pressure. I may try it on my next glue up. Pat