Who should I use my first zeta on?

This is just a suggestion. I saw a video done by operation metaverse that uses scariff rebel pathfinder instead of old Ben in that team. Scariff counters and gives more turn meter wgen he counters because of his basic. Then you wouldn’t have to worry about zeta'ing old Ben. But old Ben is still a great tank. As for zetas I’d say r2’s number crunch.