Ok, so I cheated; I did a bit of work on this a few weeks back, but never got around to writing it up. So this is really two half-afternoons' work.
The first thing I worked out when I looked at my staves and thought about it a bit, is that that nice smooth outer layer from under the bark isn't going to be the back of my bow after all. The problem is that the lighter outer layer of wood is too thick; if I make my bow from the bit right under the bark, I wont be getting any of the heartwood, from which the bow is meant to draw much of its strength. Ah well, it had seemed a bit easy that way. So the first afternoon I had a go at this I did some rough shaping of the skinniest stave with an axe and wedges - basically removing the outer cm or so of rings from the core. But the references I've found say its fairly important to try to have the back of the bow be an unbroken growth ring, and theres only so fiddly you can be with an axe. I didn't have any better tools, so I stopped.
After a couple of weeks waiting for The Tool Guy's stock to come in, I've laid hands on a draw knife and a plane. They even ordered me a spoke shave, after they looked it up to find out what one is - its a bit of an unusual piece of gear these days I think. So Jamie came round this afternoon and we had a go at the next stage of shaping until the thunder and rain arrived and shut us down:
We tried working it both ways: standing on end and lying down. Some bits were easier one way or the other, but it varied. Unfortunately I didn't get a chance to finish the rough shaping before it started raining, but we did get the sides fairly well smoothed out, which showed up a couple of the flaws I was looking at earlier:
The one on the left I _think_ doesn't go very far out towards the back of the bow, and its right out near one tip where I need to take off a fair bit of wood for the taper, so I'm hoping I'm going to end up cutting it out completely. The one on the right is about 6-8 inches from the other tip and looks to go right through - I'm just going to have to hope it doesn't weaken it too much. I'll taper less around that bit, at least to start.