Sync Values from plugins to widgets when changing variation?

Just to diagnose: When you create a widget, that loads the preset when you press it, does it work as expected?

In that case, you could try and use a one-shot trigger. Trigger that trigger from the on variation event and do the preset loading in the timer event (or whatever is the right name) of the trigger.

Some experimental features are exactly that: experimental, and they might have rough edges.