Who to R3: Galvatron or Mirage

So, at first, I wasn't even planning to consider R3ing mirage. But I wanted to complete the AM objective, had some Tech T3 to spare, so I R2 maxed. To make sure I was good with him, I took him against ROK Mixmaster. Now, some context. I had only ever seriously fought mixmaster with my R5 maxed and duped WJ, and only got him to 75%. (also a while back, but still) So I messed around with Mirage, hit some SP3, and when the fight was done and over, Mixmaster was at 19%. I easily finished him with my prowl, and now I'm undertaking ROK with a team hand-made to synergies with Mirage(The three other bots not including Prowl and Mirage are all under 1,500 PI). But I digress.

The question now is whether to R3 mirage, who is unduped, or my duped Galvatron. Galvatron honestly is good, but feels contrived in his play style, and I always am forced to eat some damage with him, even though I've played with him for a couple of months now. However, you all are all going to ask about my team. It was easier for me to list it by class. All are 3,500 and above. The one in the class I use most is listed first. And only Prowl is a 5-star. Thanks guys.

Tact: OGMT, OGP
Brawler: Tantrum
Warrior: Bludgeon, Scorponok
Scout: Kickback Prowl - I use them both equally.
Tech: Wheeljack
Demo: Tronus, (I also have a duped 4-star Galvatron. Wild)