Is it possible to key specific presets to midi pads so they can be recalled in a non sequential order?
Yes, sending Program Change messages will select different Scenes (presets).
From the manual:
Program Change Messages
Program change messages received by ETC switch to the scene specified by the message’s value. So if a program change message with a value of
1is received, ETC will switch to its first stored scene, and a program change message with value
4would switch to the fourth scene, etc.
If no scenes are stored on ETC, then these program change messages will similarly map to the loaded modes. So a program change message with value
1would switch to the first mode,
9to the ninth mode, etc.