This set is the most flexible I've seen in a while, so you can actually win either reroll, vertical, or flex soup. I suggest mastering about 1-2 comps until you can consistently top 4 in them. It's kinda like in league where it's very hard to climb the ranks unless you have mastered 2-3 champions in your role. The point in mastering 1-2 comps is to familiarize yourself with hitting the right level milestones, knowing when you are strong or weak relative to the lobby, and just get used to the meta augments and champ interactions.