Ditto on the 3X GT, it’s still my preferred amp over Volot / Ferrum stack / Enleum 23r. And preferred it still over power amps including a pair of NCore monoblocks. I have not tried op-amp rolling, but I would like to PM you for tipsCurious how you will find the CFA3 in comparison to the Soloist 3X GT. The latter is one of the best headphone amps I've own or heard. Especially with upgraded op-amps.
I am on the lookout for another amp as I toggle between two countries. Would love to just travel with a Susvara and have a good amp waiting for me in either homes.