Whistling Badger: I totally understand what you mean. From my experience I have to get almost every potential shaft at least dried, bark shaved off and spined to determine if it is worth trying to use or not. To get a shaft to that point doesnt really take up that much time, I do the stages in batches. Some shafts just come in weaker than you think they should. Experience with a certain shoot helps a lot, but there are some things you can do to better your chances for success.
1. Cut way more shoots than you want to make arrows with while you are out collecting.
2. Cut them extra long, I cut mine about 36" long for dogwood. I've noticed that cutting my shoots on one side or the other of a branch joint can make a big difference. I leave them long until dry and the bark is shaved off, then I spine them and move it from short end to bigger end until i find the sweet spot I'm looking for. Then use that information to decide where to make my final cuts to get the length I want. (hope that makes sense)
3. Cut them a little bigger in diameter than you think you will need, in part to account for shrinkage and thickness taken off by removing the bark(if you know what finished diameter is about right for a certain type of shoot), but also because
you can always sand them down a little to reduce the spine. You can stick the dried shoot in a drill chuck and spin it while running sand paper up and down the shaft to bring down the spine weight.
After collecting and making shafts a few times you will learn what to look for, cant replace experience
Thanks
Trapper Rob