Each can in the US is 14 ounce in the brand of condensed milk I found. 2 cans would be 28 ounces or 3.5 cups. What would you say the added egg yolks and eggs whites would be? Should I just double the eggs for 8 eggs or more? One can should be enough for the Original recipe but I want to scale this up because 3 hours for one can is kinda silly. At least two to make it more productive.
Bring a large pan of water to a rolling boil. Make sure that you put enough water in the pan to completely cover the can you're about to cook.
Remove the label from the can of sweetened, condensed milk and carefully submerge it into the boiling water using a pair of tongs or a slotted spoon. Make sure you place the can on its side, so it can roll around. If you place the can bottom or top-side down, the boiling water can cause it to bounce up and down, which is really annoying...
Cook the can for 3 hours, making sure the can is covered with water at all times. Add more boiling water if necessary.
Using a pair of tongs, a fork or a slotted spoon, take the can out of the pan and place it onto a heatproof surface to cool. Make sure it has cooled to room temperature before you open the can, otherwise it will squirt out like a fountain... Once cooled, stir until smooth.