Kevin, I use the Astronomik 6nm set, so very similar.
I've found I need to stay well away from the Moon, even in Ha, like 45+ degrees away. OIII is futile with any significant illumination of the Moon because of how it washes out the sky. Around full Moon is a forget-it situation for me. Anyone who says the Moon doesn't reflect Ha obviously hasn't tried it!
And then there are the gradients. Depending on the filter, the Moon can create additional gradients in an image due to it's floodlighting, on top of any local gradients from LP and horizon-dependent gradients.
I'd be interested in hearing from anyone with the 3nm for Ha, out of curiosity. Regardless, they're cost prohibitive for me at the moment, especially with the current exchange rate
