When I was using my friend's long arm I used a lot of pantos, we didn't have the software and it was just as ruler work was beginning, so I can't address the download issues, I had paper copies to work from.
The way I work/learn is that practice makes perfect and I needed some muscle memory in practicing how to do complex patterns. Some designs are much easier than others! Even if I just spread out the panto and traced it with my fingers it helped me a lot. Up here, swirl there and so forth -- also helped me decide how to work the edges and whether I could go back and forth or if it was better (for me again) to start each row from the same side.
Good luck on the software aspects, I am hoping to get my own long arm this year but think the most I'll be able to afford is a table that lends to pantos and hopefully both front and rear handles and definitely a stitch regulator. I'll be following this thread to keep the suggestions in mind for my eventual purchase.