Alcohol stove performance is heavily affected by a multitude of external variables. That makes it very hard to nail down real world performance in a controlled setting. My advice would be do practice with the alky stove in a variety of conditions to develop a good "feel" as to how it will perform in real life.
I don't know what your day to day life is like, but if you work, maybe bring it along and cook your lunch on it or make your breakfast before work, etc... Do a couple of shorter trips where you can bring extra fuel along as a safety measure.
To improve consistency you need to isolate the stove (burner unit) from outside conditions as much as possible. That means use a rock solid windscreen (TD Caldera Cone, for example, or a high walled cylindrical setup) and try to insulate the stove from the cold ground. The temperature of the surface the stove is sitting on has a massive affect on the rate of alcohol vaporization. I've been experimenting (not very scientifically) with using a piece of corrugated cardboard wrapped in aluminum foil. The aluminum foil reflects IR radiation, and the corrugations create a small dead air space between the stove and the ground. I don't have any quantitative data yet, but it seems to be a bit of an improvement.