BookFunnel and 2-step Opt in

I recently signed up for BookFunnel standard plan + email integration (Kit). BookFunnel recommends turning off 2-step opt in on the forms used with them. Kit does not recommend turning this off, but then they’re not considering a tie up with a third party such as BookFunnel in their instructions.

Should I turn off the 2-step opt in so readers don’t get multiple messages from both companies? Should I use this for existing subscribers and then duplicate the landing page. With the opt-in turned on for posting the landing page where I hope to recruit new subscribers, so they can be verified?

I hope my questions make sense because I found setting up a delivery system for new and old subscribers confusing. I don’t want my old subscribers to have to keep resubscribing every time I have a new story to release.

Thanks for any suggestions!