I contacted Slate and they can't tell me what note triggers what sound in SSD. There are Slate samples built-in to X1, which I have tried using, but they are not GM. Seems Cakewalk would support sounds that are built-in, but I can't find a Slate drum map. Anyone know anything helpful? Or at least a chart showing Slate's deviation from GM? Thanks.

The Steven Slate kits included with X1 are part of Session Drummer 3. Session Drummer 3 instruments are automatically displayed in the Step Sequencer and Piano Roll View. The drum map is similar, if not identical to Session Drummer 2. The note mapping is shown in the Drum kit and Mixer view of the Session Drummer 3 and in the help file for the plug-in. Press F1 with the plug-in in focus to bring up the help file.