Hi @InciteJoe,
I agree with @danmoyle, the email frequency safeguard feature and the option to remove contacts from workflows are great tools for this.
Personally, I would never want to receive two overlapping series of emails. From a marketer’s standpoint it also doesn’t make a lot of sense: You designed a series of emails specifically to work towards a specific goal, a next conversion, a meeting booked etc. If two or more nurturing workflows overlap, it’s unlikely that this goal will be achieved, too much going on.
In my opinion it comes down to whether you want to allow the first conversion to continue its nurturing or the last. The first makes more sense in my opinion. For your workflow design that means that the workflow that delivers the content should never contain the follow up emails. It should only deliver the content and then ‘nominate’ the contact for a nurturing workflow where they enter if they are not being nurtured already. (This can of course be solved with if/then branches in the original workflow but I’m not a fan of it. Especially with a large number of content pieces this becomes unmanageable at some point.)
Lastly, you want to think about how to deal with scenarios when contacts have already downloaded a piece of content they’re about to receive in a nurturing workflow. Here you’ll have to work with if/then branches referring to those specific form submissions.
Hope this helps!