Joe, can you go back to the nursery for the cultivar names? Knowing their growth rate could come in handy.
Your climate is so different from mine (I'm at the northern edge of heir habitat) that I don't think I'd be much of help. I did prune one of my crape myrtles the first year but only to remove inappropriate growth like suckers and inward growing branches.
I have a new crape myrtle that I didn't prune the first year because it was already branched nicely. I'm expecting its flowers to droop a bit this summer.
