Concur re proof of concept Dave. As a business, pertinent of course for GT to note continuing attendance once the initial novelty phase passes.

Similarly re the cost effective for all motivational sweet point.

I see it also as a perfect opportunity/vehicle to run advanced syllabus group courses on non-core fundamentals or style material with e.g. a 10 min Q&A session scheduled into the end of each lesson, or for instance a fast-track concentrated theory course. ie. I'm already personally on the latter via a paid, self-paced, graded, focussed course sub with another site as well, and a intense paid different module elsewhere.

Numbers by 'Plus sub' are the key to keeping it affordable here, whilst at the same time presenting its own potential problem with managable class size without a first come first served early registration restriction or moving to a pay-per-module/course limited to an xx slots availability model.

I'm chugging along full steam ahead as is, but perceive the initial recommendation #2 has potential to work favourably to mutual benefit of all, and as iterated, I'd be up for it.