Welcome Peter!
And a nice start too, both this and your other images. I have a couple of queries: What ISO did you shoot at, and also what colour was the background of one of your 1-minute subs?
The reason I ask about the background colour is because I'm surprised that you say you can only do a 1-minute exposure from your location. It is likely at least as dark as mine, and a C11 is 'slower' than my f/5 scope - so with the good guiding you seem to have (nice round stars) you should be able to expose for a lot longer than 1 minute? If you're not already aware (due apologies if you are), you can probably push the exposure up to the point where the background is significantly not black , so that the histogram on the back of the camera is well detached from the left side of the graph. You can get a darker sky back in processing after stacking all the frames, but use curves rather than clipping the black with levels or you might lose low-contrast information. You might be surprised how washed out and grey you can push original subs and still be collecting quality information (more so if you're shooting the higher bit depth RAW images too, which DSS should handle).
Anyways, good luck and have fun!