"I heat-treated and glued in about 4" of reflex but it lost all of it. "
The bow is not even 2" wide, for 135# draw weight. The least we can say is that it is an impressive feat, requiring utter craftmanship and perseverance.
Nevertheless, it also reminds me of what Badger wrote recently, about very heavy bows typically being underbuilt, and therefore not shooting as far as we'd expect from their draw weight in flight shooting.
Strain on the belly of such a bow is much more fierce than on a regular bow. Say that we'd make a 50# bow 3.5 cm wide (1 3/8"). Then for the belly to be strained no more than such a bow, it would need to be 2.7 times as wide to reach 135#, or 9.5 cm wide (3 3/4"), which is quite a ridiculous width.
So I'm very curious what the gentleman for whom this bow is intended will get out of it.