I have only tried once with deep sky objects as we have had terrible skies due to smoke from forest fires here in southern Alberta, Canada. Here is my first attempt using an X-T2 and 100-400 at 400mm on a Skytracker. I only used 10 second exposures (30 of them, cant remember). I used no dark frames or light frames, just combined in Deep Sky Stacker then adjusted in LR. I needed way more combined exposure time but I was not yet sure how accurately the mount would track with all the weight on there. I will try again when the sky is not so smokey. (I do not have access where I am now to my original file so this is the facebook converted junk)