Congrats on your purchase of the Tube Masters. I did hear them in his studio when I visited over a year ago. I heard an earlier version. Viking owners are very lucky. Hardly anyone knows about David and his magic and knowledge with speakers. I have had my Grand Voix speakers for around 6 months and I am amazed every time I listen to them. In my case I have plenty of power at 125 wpc with the Canary Audio Grand Reference 300B mono amps driven with 16 300B tubes. At 98db I don't rally need that power but the level of instrumentation space I get is extraordinary. If I ever hit the lottery I will upgrade to the Gottenburg's but that is a totally different beast.
A few of my audiophile friends on this site and WBF have purchased Viking Acoustic speakers since reading my thread.
Enjoy the music