I wonder. The problem with reposting here might be that you may not be able to publish it elsewhere later, or you could publish it as an eBook I guess.

But, what should you do? If you think actually publishing it here will help you actually get it done, then go for it. It's similar to my own situation and not writing, say, Hebrew Guides for Steemit - I'd rather focus on what makes me happy in the long term, even if it's less profitable both in the short and long term, compensation wise.

As for you having been paid for them in the past, so long you didn't sign away rights, and make it known at the bottom of a post covering said material, then go for it. If you were paid by a limited group of people, you can reach out to them and ask for their thoughts. If they paid you in order to support you, rather than for the content itself, then they'll likely support you now as well. If they paid for the content, then it's actually a lot messier, and you should talk to them and/or a lawyer.
Content on Steemit isn't actually "paid for" in this manner, by the by (for other parties reading this).

I'd do it under your current account. Just have a link to an external site with links to all the chapters, and a link to the first and previous chapters in each post. Each post should hopefully be posted 6.5 days after the last, so you could future-link. Or then again, if you know the next post's name, you'll be able to link to it even before it is written. Ah-ha!

As for experimentation, do it if you want to experiment, or if you just want to post all sorts of content. Has very little to do with anything else, I'd say.