7oz of 1.5% milk will have 10g of carbs, and anything over 20g protein is stellar, so it sounds like you are golden.
Regarding thickness of the drink; I find that the premixed drinks are thicker than when you mix them yourself, and often have a odd texture, but that (probably) comes from the ingredients they use to keep the drink mixed.
Protein drinks have come a long way, they are still powders that are resistant to mixing, but most of the better brands have the micro-powder and with an honest 20-40 seconds of shaking, will mix completely.
I also use them as a supplement and exercise recovery tool, so I also looked for the lowest calorie/carb combination. I'm not a vegetarian, but my diet is protein poor. Now that I get enough protein, my energy is way up, and I can exercise and work like a fiend. The other bonus is that having enough protein in your diet kills your sweet tooth...which in my case, is the biggest benefit.