I've made several crepe myrtle bows, it's great wood. All the bows were really fast, little moisture issues after they were made. If your using smaller diameter stuff, I suggest that you saw them in half and make sure you clamp them straight while they dry out. On some of the staves (say about 6" diameter or larger) I sawed out a 1" thick 1/4 sawn board from the middle and then dried the two halves for stave bows.
The bark on mine was really thin so be carefull when you peel it. Also if you leave the bark on it will not affect the bow, but it will give you several hundred "tick" heart-attacks
but after a few hundred shots it will stop (basically after all the bark is cracked). and you have developed a real good flinch in your release,eh?
rich
ps: mine came from south Georgia