One regular, garden variety, domestic beer is the equivalent of about .025. I had an OWI back in 1998, had to take a class, so I know this. So, two regular beers drank very quickly would get you to .05. Significant amount to get to .03? Hardly. The only thing body weight has to do with it at all is the impact it has on your body - how much you feel it. If he was at .03 he either had gone several hours after drinking a lot (body metabolizes about .025/hr), or he had recently consumed 1 or 2 beers.