I presume that by now everybody knows not to commit “Crepe Murder” (or an alternate name is “hatracking”) by shearing down all the top branches and ruining the shape of these beautiful trees.
If you need a smaller plant, did you know that there are a staggering number of cultivars of Crepe Myrtle (Lagerstroemia indica)? You can find all shades of white, pink, red, or purple (sorry, no blues or yellows), and all sized from 3 feet to 50 feet high. Some grow wide and short, some tall and narrow, with all sizes in between. So, you see, there is no need to prune your tree to the size you want – go buy one of the desired size and color. They are remarkably hardy and healthy. As a bonus, the bark of many cultivars is beautifully colored with brownish red patches, and a lightly colored peeling habit. It is wonderful as a replacement tree since it lends itself to our present residential-sized lots and neighborhoods.
There are two nurseries in driving distance (Gainesville or Valdosta) which specialize in these trees – they do advertise on the internet. I hope you find one or more to suit your landscape.
May your horticultural results be as fulfilling as your gardening diligence.