I've tried cryo'd tubes in the past, not so much for the cryo, rather for claims of hand picked. I've never had an issue, but can't say for sure I heard any difference in sound quality, don't worry about cryo vs no cryo.
While I don't run EL34 amp anymore, I question quality of new EL34, I have a number of 1990's era Svetlana, last good Svetlana. I've checked into those Decware tubes, other than cryo, nothing special. I'd try to find some NOS EL34 for best sound and durability.