As you might guess based on their names, the difference between single-rolled and double-rolled sheet glass has to do with how each kind of sheet is made.
Bullseye operates two types of rolling tables. The single-roller consists of a water-cooled steel table and a single roller. A caster spreads a dollop of molten glass across the table and guides it under the roller to insure even coverage. A single-roller allows Bullseye to make collage glasses like fracture-streamers, stringer glasses, etc. In that process, chips and/or threads of glass are first arranged on the table and then the sheet is rolled over them, picking them up to form completely unique patterns in the finished sheet.
On the second style of table, the double-roller, the glass is pressed between a pair of rollers, creating a sheet with more uniform top and bottom surfaces. In the image above, you can compare the visual and textural qualities of the single and double-rolled sheets. That is the difference! And it occurs because of the different ways they’re made, or, more specifically, because of the different kind of tables they’re rolled on.