I made a crude stand to hang the shell from. In order to get a complete scan, I was at a distance flickering between" good" and “too far.” The base of the stand kept the tracking locked. I know because if I got closer so that the base was not visible, it would not track and started the dreaded smearing. Marker mode worked too, but not as well.
The hanger is a piece of steel TIG rod that is shiny enough that most of it doesn’t scan.
