Diff. in tuning a 15wt%MeOH-water Vs. 50Wt%MeOH-water mix

[GotH2O]

15/85 mix:
got to lean out fuel to burn hotTER due to high in-cylinder cooling

50/50 mix:
got to lean out fuel due to the addition of more fuel/MeOH

What about the timing and boost?

The car is a 2.0L turbocharged mitsu evo.

just want to narrow it to either 15/85 OR 50/50 wt%. Please help.

Btw, the 15/85 mixture was chosen because the surface tension of water is very much reduced (effect tapers off as wt% MeOH increases) and I'm hoping that it will lead to better atomization and better distribution of water to each cylinder.