IIRC distance-based amplitude panning (DBAP) is the solution that best fits this case - I thought that VBAP algorithms still have some assumptions about where the listener might be / SOME regularity in the speaker placements. @woolgathering made a DBAP SuperCollider plugin here: DBAP Spatialization Plugin
One other option: DBAP / VBAP approaches are still ones that try to collapse a somewhat complex, arbitrary listener + room + speaker configuration into a low-dimensionality set of controls (e.g. X,Y parameters). This is most useful if you want to have an abstracted relationship between pieces being performed and the space/configuration - either because multiple pieces are being presented (and you need more “generalized” control), or you’re making a piece for performance in multiple different spaces/configurations.
If this is a scenario where you’re making ONE piece for performance on ONE speaker setup and don’t need that level of abstraction, it might be worth ditching ANY low-dimensionality, generic panning system and just creating semi-arbitrary panning setups per-instrument / per-sound-source. Meaning: play sound A only from speaker 1, pan sound B between speakers 2 3 and 4, give sound C area-effect panning in speakers 5-8. Three or four specific panning gestures (plus a more generic nearest-neighbor panning for sounds where close localization isn’t important) can already give a ton of possibility for articulation.
DBAP is already compromised enough that very precise spatial gestures may simply not work at all - you might end up with a highly “washed out” version of whatever you’re envisioning. Composing with specific + esoteric panning strategies (rather than a generic approach) may give you a better chance to nail specific gestures in a way that’s articulate and memorable - especially if you’re presenting to an audience that may not have deep experience with listening to and decoding complex sound spaces.