Like Pat said, there are many ways to do this…
The slow way: Split the log into quarter staves, seal the ends. Let them sit for a few years (1 year per inch of thickness in @50% RH). Reduce the staves to a roughed out bow blank. Let it sit for a few more years.
The fast way: split into staves, rough them out as bow blanks, seal the ends, and clamp each blank to a 4X6 to prevent them from warping. Keep them clamped there until dry…about 6 months or so. Or you can floor-tiller the bow blanks and put them back on the clamp..and they should dry within a month or two.
The middle way: Split into quarter staves, seal the ends. Let some staves dry for a few years. Others you can reduce to bow blanks and dry them fast or slow.
The above methods are thumbnail rules, subject to all kinds of factors like climate, RH, temperature, wood thickness, etc.
Splitting versus kerfing the log: If you think you have a good read on the log, you can kerf it with a circular saw, then split. It'll maximize your log. Don’t saw out staves. You can saw the log in half, I suppose, but I would not saw out staves. You have to follow the grain. Split them out, or do a combination of kerfing, then splitting.
If you have real good skills at reading the wood, you can saw out staves without a problem, but I'm one to opt for the safer route. So it really depends on your level of skill and experience.
I'm one for the slow way, especially since this sounds like quality yew (40+ rings per inch and I assume all other factors look equally as good?)
If I was in a hurry, I'd select one stave from the log and reduce it to a blank, and let it sit clamped to a 4X6 for 6 months or so, and then proceed to slowly craft it from there. As long as the wood is in either quarter stave form, or clamped to a 4X6 as a bow blank, it should not warp. Little skinny staves can warp, so if they are skinny staves, then clamp those as well.
Evaluating yew wood (my website):
http://analogperiphery.blogspot.com/2008/06/evaluating-yew-wood.html
