Well mozzarella has been my nemphis, but... I finally made it yesterday. Yesss
The recipe that I used is almost identical to this one with a couple of minor changes.
1. My recipe said to turn the curd every 15 mins, pouring off the excess whey each time for 1 to 1 1/2 hours.
2. To check it the curd is ready for stretching, cut off a small piece of cheese and put in the hot water. My recipe said 70c. Allow the cheese to heat up and work it with you thumb and forefinger then try stretching. If it is elastic, then it is ready for the next step. I found that it was best to do this in the water, don't take out the cheese. Also they recommended using thick gloves, and it is easier to work with your hands than spoons.
3. When cheese is ready to stretch, cut into very thin pieces and place into water. I found that the water needed to be brought back up to 70c, so I left the cheese in the water while it heated, which also heated the cheese sufficiently.
4. Mine went into an ice cold water bath first for 1 hour, then into a 20% brine solution. For a 10lt cheese it said brine for 4 hours. As I used 5lt (incase it didn't turn out again) I soaked for 2, but for me it is too salty, so probably could have soaked for 1hr.