Excercise question

That's the million dollar question. Everything is going to be estimate, luckily mfp is here to help with data tools. I would log it as circuit training general. Be honest with yourself. Just because you log something as vigorous doesn't magically mean that you actually burnt those calories.

So meow that you have your estimate you can use it against your other metrics. Assuming you are accurately logging your calories, you'll have to use your results to dictate whether or not your exercise estimate is accurate. If you are losing weight then you are probably right, if you are gaining weight then maybe you are over estimating.

I wish I had a better answer for you, but that's pretty much the reality of the situation. It's why many of us choose not to eat our exercise calories.

How do I log the type of exercise.
Would also suggest logging as circuit training.

How do we know how many calories burn ?
You don't. It's not possible or necessary to be accurate - it's a rough estimate based on METS.

Exercise calories are just a small part of the puzzle - your actual results over an extended period of time will confirm if your calorie balance is working or not.