how would you track Chris Powell DVD?

I wore my fitbit during my workout today, but it says I only burned 120 calories during the working. I'm thinking it's much more than that as I'm 258lbs. How can I get a good estimate using the MFP database? Low intensity Aerobic? FIW - If I do use that one, it give me 290 calories burned.

**I have a HRM, but haven't worn it in months. Need to dig it back out. Didn't realize my fitbit wouldn't calculate non-walking type exercises well.