Barrister planning a legal-education business for SME owners — advice on validating and pricing appreciated

I'm a UK commercial barrister, and I've also been involved in building businesses, so I know both sides of this problem: business owners routinely get priced out of legal advice, and by the time contracts reach someone like me, they've already gone wrong but it was totally avoidable.

So I'm building a plain-English education business teaching business owners to understand key clauses so know what they are signing up to, be more contract confident and work out when you genuinely need a lawyer (and be a better-informed when you do so you aren't over-serviced/charged).

Where I am: course outline drafted ("The 10 most costly contract lessons for entrepreneurs"), planning a small free pilot cohort for feedback before charging and spending a few hundred pounds for paid-ads validation.

Where I'd genuinely value advice from people who've built businesses:

1. Validation — those of you who've launched a product/service: what actually told you there was real demand, beyond polite interest? I'm wary of waitlist signups that mean nothing.
2. Pricing — one-off course vs. monthly membership for on-going support for this kind of audience: what have you seen work (or fail) as buyers or sellers?
3. Channels — where do you pay attention as business owners? Is it the usual Facebook, Google etc
4. And honestly — as business owners, if a version of this had existed when you started, what would have made you do it? Or would you just not care enough about it in reality.

Appreciate any guidance/insight people can bring.