Another thing to be weary about is hypo's the next morning...
The liver can't process alcohol and process glucose for your liver store at the same time, so it will stop process glucose to store in your liver, and process the alcohol out your system, and once your liver has dribbled all it's store of glucose into your blood stream, so your background insulin effectively becomes quick acting insulin.. (background insulin is inject to tackle the glucose being delivered into your blood by the liver) so increases the likely hood of hypo's, and also means that a glucogen injection is useless if you hit a hypo. You will have to have fast acting carbs either to eat or a glucose mixture straight into a vein by a paramedic...
It takes on average around an hour for the liver to process 1 unit of alcohol..
I don't drink, but hubby does (he's T1 as well) and he also has some form of slow/starchy carbs before he goes to bed, to ensure he doesn't have an hypo.