Strategies to Build an Engaged Slack Community: 1:1 Communication vs. Wider Marketing

Hi folks, getting a new Slack community off the ground. I'm wondering if there is an equation (i.e size of community + experience of member) that leads to most engaged group? After speaking with Zach H., I've identified 20 individuals as potential founding members and am thinking about whether marketing to the wider community or focusing mostly on 1:1 communication and word of mouth will reap the best benefits for the group.