It is always wise to keep your alcohol intake down to 2 drinks maximum for an evening since most people can maintain self-control but when alcohol is combined with other drugs it usually takes human clinical testing to determine the exact results. One test done on alcohol intake with cannabidiol (CBD) produced the following: "Compared to placebo, alcohol and alcohol plus CBD, but not CBD alone, produced significant impairments of motor and psychomotor performances, overestimations of time production and subjective responses indicating an accurate self-perception of their intoxication and deficits. The combination of alcohol plus CBD resulted in significantly lower blood alcohol levels compared to alcohol given alone, however, there were few differences observed between the pharmacological effects of the two alcohol conditions. Thus, the inactivity of CBD, a major marijuana constituent, on motor and mental performance and effects also extends to its interaction with alcohol." Psychopharmacology (Berl). 1979;66(1):45-50. Interaction of cannabidiol and alcohol in humans. Consroe P, Carlini EA, Zwicker AP, Lacerda LA. In other words, you're safe if you stick with your CBD Cannabis but it is best to not mix it with alcohol because you could become impaired especially in terms of your reaction time and that's when accidents can happen.
It is quite common, although not advised in my opionion, to consume alcohol while also consuming marijuana. In a recent research study, readily available on PubMed, there was a study released on the interaction of cannabidiol, or CBD, with alcohol. In this study it was shown that when a person consumed alcohol with CBD, there was "significant impairments of motor and psychomotor performances, overestimations of time production and subjective responses indicating an accurate self-perception of their intoxication and deficits". Interestingly, when combined with alcohol, CBD resulted in far lower blood alcohol levels as well.
The other thing that may affect how you do if consuming CBD and alcohol, is your method of ingestion. Anecdotally, some people have reported they feel more impairment when vaping CBD. This may possibly be due to the fact, that there may be a ratio of CBD to THC as well. It is well known that the effect of THC is magnified when consuming alcohol. This is due to the fact that THC is dissolved by alcohol and essentially doubles the amount! In a recent study,"Interaction with other drugs: metabolic interaction", it also showed that when cannabis and alcohol are consumed together the effects are longer lasting.
Personally, it seems that recent research indicates that consuming alcohol and cannabis together are not a good combination, whether it be CBD or THC.
These comments represent my opinions, I am not a doctor. I hope this helps, Pamela