Upload & Sell: On
You only ever use one roll at a time - so why does it matter even if two line up? ...Always the rolls fall at the rear of the arms because the INSIDE of the rolls are what you need to use as your background surface - not the outside. There is a RIGHT and WRONG side to paper and material even. The RIGHT side is the inside.
If you're using the paper for full-length sweeps, then yes, it's easier to unroll from the back so the sweep follows the natural curve of the paper; but if you're using the paper as a BG only, with weighted ends as we did at the studio where I apprenticed, it helps to have the paper rolls hung alternately so the weight bars have clearance to move past each other. In the latter case, the side of the paper facing the camera is immaterial.
I wanted to double check this, in case manufacturing processes had substantially changed in the last 20 years and there was an actual difference in one side of the paper over the other, so I e-mailed Savage Universal and this was what I got in reply:
"Seamless paper can technically be used on either side. The "right" side however, is on the inside of the roll as it is unwound. Using this side preserves the color against fading, and also makes unrolling it out for a proper "sweep" much easier."