I heat treat somewhere between floor tiller and brace height.
If you aren't going for a LOT of reflex, allow me to suggest toasting the bending portions flat and straight, and putting the reflex right at the base of the levers. For some reason doing it this way has always seemed to make it easier to tiller and keep the profile throughout the tiller.
I have set the limbs forward slightly at the handle to create a couple inches of reflex, but that seemed to complicate getting the inner limbs to bend evenly. Like they were stubborn right off the fades, and when I go that fixed, then they acted too stiff closer to the transition, and took more set both bows I made.
It worked better when I tried reflexing the levers into a smooth gradual curves, (again about 2"), but that also made the "outer" inners want to bend too much, and seemed to add some lateral instability (vibration at release).
My best mollies had the whole middle, handle and bending limbs straight and flat as a board once tempered, and just a slight angle forward built right in at the transition, again 2" or so. If you have the width, the middle will take almost zero set.