Id suggest a good floor tiller close to your intended weight, then temper, then back, then finish tiller. If you don't try to temper the bow when its still 30# over your intended weight, you don't have to temper twice. And, if you temper correctly its through the thickness anyhow. Often times when folks have to temper again, they are really only heat shaping the wood a second time. When you heat shape to early the extra stiff limbs wont take as much shape as they could if they are closer to finished thickness and you end up tillering out the small bit of reflex you added. Hence why the "second tempering" usually sticks, very little wood is removed afterwards and the bow holds its shape. Not really a result of tempering, just heat shaping at the right time in the process.
