The *actual* number is not important, by simply adding meth to the mixture in various quantities all you will do is alter your running AFR.
SO if you always aimed for 11.7:1 on WOT and max rpm then you will aim for this SAME number with the meth/petrol mixture, just as you would if you were running 100% meth, its no different.
Think about it for a minute and you will understand the logic of it
The *correct* number has no relevance except for when you wanted to calculate back another figure from the correct AFR balance for that fuel type or fuel mixture ratio blend.
This is applied in Autronic ECU's for example, there is only a target AFR table based of petrol stociometric scale (14.7:1) and all the numbers that follow to make sence regardless of what fuel type your running. Just as Lambda is a number so too is Petrol AFR and its values, your targets will never change regardless of what mixture or blend you run :idea: