No reason to beyond 15 degrees
The boat slows down and starts to get pushed around (leeway) after 15 degrees of heel. I still let it go to 20 on occision, just out of laziness. It is still pretty comfortable. While you are new, don't go beyond 20 degrees. You will scare people and strain things on the boat. In reality, it is nearly impossible to tip the boat over. If you are at 30 or 35 degrees, the leeway increases, wind begins to spill out of you sail. The boat will not go completely over. However, you and your family will be scared, sailing will be an unpleasant experience and things may break under the strain. If you really want to get used to pushing a boat, you should crew on a racing boat. You will learn a lot, get used to the feel of the boat and meet great people who will help you as you build your skills. It is a very open community. Sail your own boat for fun.