Which 300b amplifier for Devore O/96

Try the unknown brand Canary Audio you will love them 

Of the list you provide, I would only choose the Nagra if you like a less traditional tube sound. My experience with Air Tight is similar to the Nagra. I cant comment on the Wavac due to limited experience. The Shindo gear is great for a more traditional tube sound and what Luxman I have heard errs to the pleasant. 

But, in my experience, both push pull and SET designs are inherently somewhat flawed and in somewhat opposite ways. With the right speaker I have yet to encounter a better design than an OTL especially if you really want to hear what is going on with your software.

 Coincident Frankenstein Mark two is probably one of the best 300 B amplifier available at any price. Dead silent with the most natural life like sound with midrange to actually die for. Extremely highly recommended 

My experience with 300B has been pretty good having used a number of them. My favorite would be the Sophie Electric. They have both mono blocks and integrated......highly refined and plenty of power for the Devore's. 

I was in the amp shootout mentioned earlier by jsautter and I also built the Audio Note Kit 300b interstage amps used in the comparison - I wanted them to win! In fact, prior to the shootout, the Devore's sounded terrific with the Audio Note amplifiers and I was quite confident they would win.

I'm not technically savvy like many on the forum, but from just a listeners perspective, with the Devore O96's, the Atma-spheres are magic, even against some very strong competition including the Audio Note's and the Vac. They were detailed yet smooth, and the bass response was amazing but not muddy. 

It's tough sometimes to know how certain combinations will sound. Most of the time you have to guess. I'm sure there are other amps, some worse some better with the Devore's. But I know the Atma-sphere's are a great match and not something a Devore owner would regret.