Still need advice

I have recently started using meth iv. I have the application under control and getting better every time. But I want to feel the hit when I do it so my question is what amount water ratios Is more water better or should I only use enough to make it a liquid. Thick or thin. Using basic harm reduction supplies and new to this. Need help to get desired results without going to far. Did .15 at around 3 followed by.1.5 at around 10 pm almost dont feel either of them. Got a good sleep so I

Not sure what to do? Hit another .15?