I'm doing the happy dance for you!!!

Answers to your questions:
1. Yes
2. You can just test and dose in the evenings.
3. I'd wait about an hour to give it time to mix well. You don't want somebody swimming into a 'hot pocket.'
4. I personally don't use it because I am diligent about my chemistry maintenance. Some people do. It won't hurt but isn't really necessary. If you do decide to use it, know that it will make your FC plummet when you add it. (It is more of a preventative. Once you have algae, it isn't that much of a help. At that point, you just need chlorine and lots of it. You know all about that, don't you!)

You are very welcome. That is why we are here -- to help, educate and encourage. Now, go swim and enjoy that pool!