I'm not big on tactical white lights for sidearms. I'm not against them, I just rarely use them. I'd purchase a green laser/Viridin brand with a strobe feature.
For regular white lights(no laser aiming units), see
www.surefire.com .
Surefire has been standard issue to many LE & military services worldwide.
They are made for hard use & have bright lights.
That may help with your white light needs.
Clyde