For these ones you need to get a clear picture in your mind of how you think this stave in going to look with perfect tiller for its shape(rather than perfect tiller on a perfect stave)
I do this by doing a drawing of the stave before tillering, relaxed, and also how it should look strung and at full draw. If you don't do something similar, it can be hard to keep each limb doing its fair share of the work, even if the thickness taper is correct. If you put it down for a couple of weeks and don't have a drawing, when you start again it's easy to get confused, whether its bending properly, or whether one limb is taking too much set in relation to the other. Without a hard reference you won't be able to tell.