What is the optimum amount/type of cardio to reduce body fat??

I am currently strength-training 3x per week, getting geared up to do BFL (i.e., currently I am alternating UB and LB workouts, 2 exercises for each major muscle group, 15x12x12x10 reps each, same weight on each rep., no "high-point" thing as of yet). I've always been into cardio, 6 to 7 days a week prior to lifting weights, and have now cut back some and am working on the 20 MAS, which means A LOT less cardio than I was used to doing. It doesn't seem right to me to limit cardio to 3 days a week for fat loss. I feel like I should be doing some cardio on weight days as well, and more than 20 mins. on my cardio days.

While I definitely want to build muscle, I have quite a bit of body fat to lose. Is this the optimum amount of cardio for fat loss?