@whatnow As a long-time full time info-product producer, let me offer you an alternative strategy, exactly what I would tell a member of my info-biz course if they presented the same scenario:
DON'T squander the chance to turn the 'info-biz' aspect into a real, viable, long-term opportunity.
Don't sell the book initially, instead create a 'short report' with a few 'nuggets' from the course and use it as a lead magnet (an 'opt-in' giveaway in return for email address).
You'll have more opportunity to place or offer the lead magnet, and grow your list faster & bigger.
THEN use your list to send out a weekly newsletter of relevant tips, ideas, inspirations, etc. (to maintain an ongoing relationship and reinforce your status as a worthwhile trusted resource. You can write it yourself, outsource it, or curate relevant stuff).
When your course is close to ready, build up some anticipation and excitement 10-14 days prior.
Both before & after, consider looking for relevant worthwhile offers you can promote to your list as an affiliate.
Finally, once you've launched your course and have some numbers, find affiliates to promote your course.
Fwiw, along with producing info-products as my primary full-time income, I created a course on how to do what I do - a scenario just like your btw.
If you'd like to PM me, I'm willing to give you access to the course gratis (it's $250 if you were to sign up); in addition, I would be happy to work with you to help you succeed on the info-biz side of your efforts.