I do. I never heard that you couldn't. All the GL1500 rider that I know that have put the Compufire Alternators in have switched to the sealed batteries and use a trickle charger during the winter.
From the Northwest Corner
A battery tender has such a slow rate of charege that it should be fine on any 12v battery. I've used one for years, but don't have a gel battery either. I would consider one if and when my battery goes pffft.