Cugila, I think some of what you are suggesting is a bit incorrect.
At the risk of being too technical, I'll try and say how it works. Those who don't want the explanation, jump to the last paragraph
The rise in BG from alcoholic drinks will come only from the sugar in them, either added or left there unfermented. It is the anaerobic metabolism of glucose by yeast that produces the alcohol and although ethanol is a carbohydrate, it doesn't metabolise to glucose and won't raise BG. The sugar in the drinks will of course.
Instead, alcohol is metabolised, mostly in the liver, to acetaldehyde which is converted to acetic acid (the same as found in vinegar) and then to something called acetyl-CoA. This last chemical appears in a natural part of the process, called the glycolytic pathway, that breaks down glucose so it simply feeds into that normal metabolic process. The last part of this chain is called the citric acid cycle and accepts acetyl-CoA as its input. Alcohol takes a short cut into the same process that glucose goes through.
The liver doesn't need glucose to process alcohol. And there isn't the competition between these processes that you suggest. Instead, alcohol affects the hormones that regulate the production of the enzymes that control the balance between breaking down glycogen to produced glucose (to raise blood sugar) and the glycolytic pathway which metabolises glucose (reduce blood sugar).
You should think of the liver as a permanently working chemical factory producing thousands of products simultaneously, and the delicate balance is controlled by the concentration of enzymes which in turn are adjusted by hormone levels.
The BG reducing effect of alcohol is because the balance is adjusted between glycolysis and gluconeogenesis by a wide range of mechanisms. Both processes are going on at the same time and are controlled largely by the same groups of enzymes and the overall effect is that alcohol inhibits the breakdown of glycogen into glucose. At the same time, the increase in the concentration of acetyl-CoA (from all the alcohol) changes the balance of the processes too. It can be quite an individual response - some people will see a rise, and some a reduction in BG depending on the state and activity of their liver.
When too much alcohol is taken, the oxidative capabilities of liver tissue are temporarily exhausted and ketones are produces which are toxic. These produce the symptoms of alcohol poisoning.
The upshot of all this? Some alcohol will tend to depress gluconeogenesis, so will tend to reduce BG. Too much will disturb the balance with less predictable results. Regular huge excess will kill liver tissue and produce harmful metabolic products. I hope that helps clarify the biochemistry in case anyone is interested
