Hi Joe,
That seems to be the common belief, but I and many others have not found that to be 100% true. Each serves a different purpose to a certain degree and there it some good historical data to indicate that a M50/W50 mix works well, but many of us in the US have found that using more methanol allows us to make more power... maybe just because of the oxygen content of this fuel... I don't know, but we've found that we can maximize a combination to make more power with high methanol concentrations than we can with a 50/50 mix. Unfortunately, many WI systems can't handle the undiluted methanol so a system has to be built around it's use.
Lets try to stay on topic in this thread... if you want to talk more about this, there was another thread on this topic a little while back....
http://www.aquamist.co.uk/phpBB2/viewtopic.php?t=673