You can use air assisted nozzles to break the water/methanol down even finer. They have been used in pre-turbo setups and no damage that can be seen with the naked eye anyway.Yeah Pro Meth Immediately came to mind. They also have a volute injection system.
I don't think you can get away from damaging the compressor by spraying at it; liquids are a lot more dense than gases. Turbos weren't designed to compress liquids, nor to phase change liquids into gases. That said, spraying pre-compressor etc effectively extends the compressor's efficiency. So there are gains to be had from it. All comes down to your willingness to replace the parts as necessary.
Since this is a bike not a car, using C02 assisted system makes the most sense.