Here's my exploratory first light. I used the filter to make sure that I would have some obvious bands in the spectrum. Top image is a 2-second exposure; very little trailing, but the fact that you have a Bayer array in the DSLR introduces avoidable noise. A one-second exposure would probably be a sharper, but more noisy spectrum. The second image is a 30-second exposure, with the lens' rotating collar used to orient the trailing so that it is orthogonal to the spectrum. At this juncture I was still ignorant as to what really matters, and obsessed needlessly to get things oriented "perfectly". Still not quite achieved, though nearly there. The only practical way of getting the orientation close to perfect would be to use a laptop, but then that would not be snapshooting, would it? So, now I know, do not obsess. Just rotate the spectrum to horizontal in an image editor, and then use warping or perspective correcting tools in the same image editor to skew the trailing so that it ends up orthogonal to the spectrum. Next we want to "bin" vertically to average out the noise, no need to take dark frames. Collapse the vertical size to one or 2 pixels high by "resizing" and then expand it again to whatever height you want it, again by resizing (without constraining aspect ratio, of course). I ended up with the bottom image. Nice :-)