1. Have not written CLR functions yet. This is because I haven't encountered a situation where T-SQL couldn't cut it so I haven't looked into them thus far.

2. N/A

3. N/A

4. If I had some kind of really intricate string manipulation or needed something in the .NET that I couldn't figure out how to do in T-SQL I'd look into it. So far I haven't come across anything like that.