I think you’ve hit the limits of my understanding of the electrophysiological context. I don’t have much in the way of advice here. I would generally say: Organize the data as makes sense to you within the context of BIDS. If you’re able to mix and match pieces without breaking validation, that’s good. You may want to consult with the makers of tools for processing the type of data you have about if there’s a convention they’ve adopted. If that maker is you and there’s nobody else processing the same type of data, your need for consultation is probably limited.