Frequency is probably the second variable to consider (strength being the first). And I think environment has a lot to do with it as indoors will be different from outdoors in the weather. Your's is also slightly different being outdoors but covered from rain.
I think
@Bode uses his right before a rain event in his outdoor setting.
I was thinking maybe after stretch, and then again at maybe 6 weeks just before bulking up before the buds swell and it's harder to get into the nooks and crannies.
And I think rinsing off would be counterproductive. As I mentioned in the first link I pointed to, think of it like this, microbes are all around us, everywhere on every surface. When we spray our mix we are trying to cover the surface with more of the microbes we are trying to promote, essentially covering the battlefield with our troops that hopefully overwhelm the bad ones.
Control of surface real estate is how the microbes live and if the surface is covered with those we want there is less available to the ones we don't. So, rinsing the surface off after applying would seem to clear the battlefield somewhat and make it a more open surface for new competition including molds and bud rot fungus.
So, I spray and let it dry before lights off/sundown and just leave it. But I also bud wash at harvest which I think is a better time to do the rinse. That said, I don't teally have much of a play book. Perhaps
@ChefDGreen can offer his thoughts on frequency and possibly rinsing off as he seems to have a bit more working knowledge and experience with using the Microbial sprays.