@Hooroo link I provided says a 130kg male is safe having drunk 6 cans of 4% alcohol over 3 hrs but borderline at 7.
After 12 cans you are going to lose your licence and will need to leave it another three hours to be borderline and four to be sure. All of the above is for the 240 limit
You can drink 10 cans in 3 hrs and be just under the 400.
Don't blame me if all the above puts you wrong as there are so many other factors that affect alcohol absorption. I would definitely keep a buffer below those limits