Testing

If you're eating enough in your main meals then "snacking" shouldn't really be necessary.
If you up the fat/protein content and rein back the carbs you'll get fuller for longer and the snacks should become history.

The more you test the better in my book. However before my CGM, how much testing I did depended on how I seemed to be doing for the day. I would test anywhere from 3-8 times a day, but I was on insulin and so it really mattered.

I am going to assume you are not on insulin as a type 2? So testing is more so you know which/what foods how you are reacting and how they are changing your BG level. Maybe also so you know how careful you have to eat the next snack/meal? Or exercise etc. And mostly to make sure you are getting control of your Bg levels.

So I believe how many times a day would be up to you. However if you ever don't feel "right" always test!