Trying to figure out how many user seats we need

We are an organization with 5 developers, but all of our projects are open source. We are mostly interested in a paid plan in order to have more builds going in parallel and also because a couple of our projects would benefit from larger build environments (e.g., more RAM for docker dependencies). So can we get by with the minimum of 3 seats, or would we need 5?

I’m also not sure how we can make use of the Open Source plan (400,000 credits/mo. for open source builds). Is it because I authorized CircleCI to see both public and private repos, even though we only use CircleCI to test public repos?

You might have better luck with the details of this question by reaching out to the sales team.