I use CD-RW and CD-Rs in my stacker without any jamming so far (7 months). The trick is to use the branded media where the dimensions (thickness, diameter and twist) are actually part of the quality control process.
For CD-R, I use Ricoh Golds, and for CD-RW I use Ricoh 10x (purple ones), Verbatim 10x, Verbatim 12-24x and Imation 4x and 10x discs.

And I NEVER EVER stick any labels on the discs. That is just asking for trouble. Labels cause the disc to go off balance when spinning. A majority of computer CD-ROM drives have built in vibration damping mechanisms (because they spin so fast at up to 50x), but I doubt that audio CD readers have the same.