I think your plan will work just fine. HST (full body workout) 3 x wk and cardio on your off days. I really like HST, I used it for a good 1.5-2 months. It's a good change in routine and gives you time to do other things. It's kind of a circuit, so it'll help you burn fat so long as you take shorter rests between sets. If your diet and cardio are in check I think you'll see positive results.