I've been doing a version of this with a sort of "inverse triangular" scheme related to the type of drinks I have. My goal was primarily to have more nights of the week where I don't drink, and secondarily to reduce the amount of beer I drink, mostly for the reduced calories.
I've found that I don't respond well to goals which limit the number of drinks I have per night; there's a lot of reasoning upthread about why that's the case which I agree with. I've had much more success, though, with the following system:
Start a "Do more" goal with the units "Days without drinking." Set the rate appropriately .
Give yourself the following points:
1 point for a day with no alcohol
.5 for a day with no beer and only one drink
.25 for a day with no beer
I've found that my incentives are to drink less beer (good!), to drink more wine and liquor on nights when I have a social reason to drink (less good, but good overall for my total calories), and to have more weeknights when I have no alcoholic drinks (great!).
 Mine is set to 2.8, which is the appropriate rate to force Weekends Off to behave in such a way that I'm required to have 2 days during the week without alcohol. Other appropriate values are 1.4, 4.2, 5.6, or 7. YMMV, and you may not care about having weekends free to drink whatever you like, so of course everyone's ideal behavior will vary.