To all of you offering advice, it would appear that none of you know anything about the M6 phono and your recommendations could be flawed.
The Audionote phono/SUT solution appears to use a MM gain that is very low, much lower than most MM phono sections and very high gain SUT's.
Can one of you boffins correct me if I am wrong but 126mv to 1v suggests the MM phono only has 18db of gain. The audio note transformers appear to be 30-100 times gain.
This would suggest that if the Koetsu is double the output voltage of the Audionote MC's then he would need half the gain of the Audionote transformers to get the gain write FOR THE AUDIONOTE M6.
I'm guessing something around 1:15 turns should be about right for that weird M^ phono - Denon AU-S1 at 1:14 might be a good fit.
It is very unfortunate that Audionote does not give out enough specifications either in the manual or on their website for their products.
As regards the comments above, personally I would not buy a SUT recommended from a manufacturer who makes recommendation without even bothering to check what the phono specifications are. Recipe for disaster.