Best 300B tube for Cayin 300B amp?

oceanica...i just replaced my previous sophia 'princess' with the new sophia 'royal princess' and it is much-much better. read the new review on positive feedback magazines website by jeff day...it really is great.i have about 20 hrs on them and they keep improving but right out of the box were significantly better...soundstage..bass ..mids ..everything...

isochronism....i have chalice audio 'grail' SET monoblocks...chaliceaudio.com...the 300B tubes..1 each amp..are the driver tubes in this configuration...( see pic in my 'system' area)..the 'royal princess' tubes are not cheap...~ $ 1200 / matched pair...but they are much better then the sophia 'princess' tubes they replaced and worth the price..hope this helps..dave