Here are some photos of the weight comparison between the different batteries I have been using.
Aircraft Weight RTF w/ SFGs W/O Battery: 4 lbs 13.8 oz
Battery 1: Flight Power 6 Cell 3800 mah 70C
Great pack to get maximum flight time which is around 6-7 minutes according how you fly. A little on the heavy side but plane handles it very well. The 70c allows for maximum power throughout the entire flight. Easily fits in the plane.
Battery 2: Flight Power 6 Cell 3600 mah 50c: 1 lb 4.0 oz.
This would be my second choice if you are still wanting the longer flight times, but keeping it light. Great power throughout the entire flight. Flight time is around 5-7 minutes according how you fly. Easily fits in the plane with no problem
Battery 3: Flight Power 6 Cell 3350 mah 30c: 1 lb 2.0 oz
This has to be my favorite pack so far. It is what I used in the latest video flown with SFGs. You will get around 4.5 to 6 min flight time according how you fly. Plane flies VERY light with this pack and can do some awesome tumbles with it. Battery fits great in the plane and the CG is no issue.
Above are my thoughts on the battery. Using option 3 keeps you under 6 lbs easily. My next step is to order a 5 cell pack and see how well she flies with it.