gains
 

what gains are there to be had from using alcohol mixture as i am currently using distilled water only.also which is safer?

It depends on the pump you're using.
Some have seals that won't tolerate too much ethanol or methanol.

In the winter it also stops the tank from freezing, and it also helps reduce surface tension, so there are a few positives to consider as well.

im using a race pump rated at 13.8v and flow rate of 250ml @100psi

The curent race pump is capable of injecting 330cc/min.

Running methanol mixture greater than 50% may affect your air fuel ratio, can you trim fuel to accomdate. Running up to 75% methanol is possible for the aquamist pump.

When changing from 100% water ro 50% methjanol will require you to increase nozzle size by two steps due to less cooling property of methanol.