My experience with purpleheart for self bows has been like badgers(though I only tried 4 staves rather than 30). They were around 1&3/8" wide and flat(though faceted in the Torges style, but not a true elb)bellies, bend through the handle, around 66" btn.
Very straight grained pieces, well tillered but most blew in tension, near or at full draw. Another 4" of length and they probably would have been safe, but I only had 67 or 68" lengths at the time. I don't think any of mine chrysalled though I was aware it was very possible. If I was to have another go I would use longer wood, and maybe a thin hickory backing. PH is just too expensive down here in Australia to muck around with. I mainly use it as a core lam, where a little bit goes a long way.
I do remember an article perhaps from the defunct Instinctive Archer magazine, or an old issue of PA a guy in the 1940's who made a purpleheart self elb, around the 40lbs mark.