Both the 7D and 5D MKII have the exact same bitrate and video quality. There's no difference other than some effects that the 5D has but that doesn't affect the size. While the h264 isn't the best codec to edit natively, it can still be done. The best way to do it would be to convert to prores so it's less taxing on your computer, but if you aren't dealing with much footage or don't have time, native editing works just fine. If you don't have the patience for the slow render times then good luck with your initial conversion to another codec.