Hello, Craig,
great picture,congratulations.
Last autumn I did some tests with the Infinity Mono with a 12nm Astronomic Ha Filter.
A stack of 20 images with 50 seconds exposure each had a higher noise than a stack of 20 images with 35 seconds each.
The image is a combination of 31x20 seconds B/W with 15x35 seconds Ha in false color. (For Ha too few pictures ... )
At the moment I suffer from the "white nights", it doesn't get really dark (53 degrees north latitude).
Have fun
Klaus