[rotrex]

avoid turns, hence direct port.
otherwise you will lose a fair share of the water droplets on the way to the combustion chamber.

nozzle size guidance from RichardL is a good advice to get going:

1.5cc/Hp of a 50:50 mix
2 for 100% methanol
1 for pure water.

so for a 500HP engine, you need to inject some 750ml/min of a 50:50 mix and retune.
without ignition and fuel tuning you will lose power.