I think there's the whole Farenheit/Centigrade thing going on here
... I recon on about 200C for heat treating... which is, as Marc says is say well over 300 F (~390F)
Personally I've gone metric every inch of the way
I agree with the point about needing insulation, that's the great thing about a heat gun, you can direct the heat and shield sensitive areas.
Almost needs an oven with adjustable sides so it can clamp down on the sides of the timber leaving the back outside the oven and the belly exposed to the heat... a bit impractical
On the other hand maybe slathering the back with clay, like they use on knives when heat treating?
Del