Woah woah woah wait a sec. So if I install LauncherPro and still have widgets on any of my 5 stock homescreens, it will be effectively updating junk on both screens? Cuz if so then wow thats bad.
Also I don't think LauncherPro really does anything for battery life. If anything I'd say it could help your battery life by turning down the # of homescreens and making it run smoother, less load overall. I've been getting 40+ hours off the charger, hitting 15%/20% battery life using LauncherPro.
By the way, LauncherPro rips stock a new one. The only thing you'd be missing out on are the Motoblur widgets, if that matters to you.