
Some call me Tim |

I don't think this was ever intended to give a more or less permanent boost with a trick like this.
Here's how I would rule if I was DM. I'd say it is drinks per hour. With the body able to metabolize one drink per hour. So as long as you never drank more than 3 drinks an hour you wouldn't get sickened.
However, I'd say if you drank once an hour every day, I'd start to have you make rolls to avoid possible addiction as noted under the rules for drunkenness. I might just set the DC to number of drinks you had that day. I'd probably allow 2 * Constitution modifier +1 drinks per day without worry.
So, you could do this for three hours a day with a problem. That sounds about right. If you really needed it more than that you run the risk of addiction.