I can't see why this wouldn't work if no new bond holders are allowed to join. I'm not an expert on your local law though. I think I know the issue your having and as long as money changes hands for new bonds there shouldn't be an issue. Capping purchases at a proportional amount to ownership May be an issue but bond holders could hv a hand shake agreement to only purchase their fair share
There are multiple issues, local and federal. The main issue is specifically pertaining to variable payout though. I'm not a lawyer so I'm waiting for my legal rep to put it all in legal terminology before laying out there.
With fixed Hashrate you would still pay variable payout... It will change each week..