I was 18 and knew everything. The session cost about $9 and I desperately wanted to take it back, as the next day was a nine hour bus (with knackered suspension) drive up to the Cloudforest.
The only calculated amount I can think of (I've never counted before) was a triple tequila (that was the accepted measurement in the bar) every ten minutes and the chap I challenged did 9 of them to my 8.
That's 24 units in 70 minutes. Half a bottle of wine before that and two litres of beer...