Earmax Pro tube roll....help a lost soul

Just got me a brand new Earmax Pro. From what I understand this headphone amp can be greatly improved by swapping the two 6922 tubes and the single 12at7 tube. I could use some advice from fellow Earmax Pro owners, or people who have had great experiance with either tube. I like a tight, detailed, ever so slightly warm sound sound with fast dynamic transients and no "tube mushiness". Highs must be detailed and airy.
Thanks so much my fellow audiophile friends
dudeaudio