I have tried both dry heat and boiling in the last month.....the dry heat was not successful and I only achieved a small "flip" of the tips and had real issues with cracking.
Last week, I put some ~60 degree recurves in the tips of a 62" stave that was just over a half inch thick where I bent it. I had some very minor surface cracking, but nothing unexpected and it went better than I was anticipating. I boiled the tips for an hour in a large stock pot covered with foil and then bent them ASAP on my jig with a sheet metal strap over the belly, which appeared to be effective at preventing splinters. I definitely wouldn't go less than an hour on a half inch thickness though. It definitely was not as flexible as osage would have been with similar treatment.
Matt