The cowboy boots tip is good as they're the "poor man's" orthotic insert substitute. Orthotic shoe inserts can really stave off sciatica attacks and they're realtively easily obtained. I have a number of associates who swear by the results, I'm just darned lucky enough that a bi-yearly chiropractic visit is all I've needed.
The other answer you probably don't want to hear: the cowboy vs jockey riding postion...back problems are less like to flare up if you ride jockey style and keep your weight on your legs and not on your spine/tailbone. Mid sets might be a quick enough solution to satisfy the Speedy/America design but I'm betting a sport bike posture is better in your situation supporting your body with your thighs and not your injured back.
