At first I used just water but the result was uneven, so I bought some glaze medium. The suggested 1:10 mixing ratio is about right but the gel is still as thick as the pure paint. When I paint I get stripes from the edges of the brush. I tried to thin it with water but the problem persists. When I try to glaze my layers are often uneven." -- Kyrre
I'm an oil glazer usually, but I do have some Daler-Rowney Glaze Medium and have used it with acrylics. It is much thicker than the oil glazing medium I use, but I think you can do some good work with it.
You mentioned a 1:10 mix of color and medium, I go much further than this, maybe even up to 1:50 (see my ratio of paint to medium). I'm looking for the barest tinting of the medium. No, you can't use too little paint. When it's not a deep enough color, you can always add more glazes once it's dry.
With less paint, it will be easier for you to mix with your brush, or you could use a palette knife. I mix such small amounts of glazes that I just use a brush, dipping the tiniest hair or three into the paint then into a dime sized puddle of glazing medium.
To be rid of brush strokes use only the least amount of your mix and spread, spread, spread. As long as the paint underneath is dry, it will spread and thin out on the surface well. Also, once your glaze is in place you can use a very soft fluffy brush called a mop brush (it's the shape of a women's blush applicator brush) to basically "dust" the area free of brush strokes.
I don't think you can have an exact measurement of paint to medium because some colors are much stronger than others. I have to really watch Light Red for instance. The tiniest bit of that color goes a very long way. I just try to make the mix equally transparent, however much paint it takes in each color.
