I don't think mixing fats and carbs is something DC is concerned about, that started with John Berardi at T-mag. I think it holds water for those of us that tend to gain fat easily, but from what I've gathered from you this isn't the case. I think at this point you need to just get the calories down whichever method you find easiest. I wouldn't even worry about fat gain until you start to see the scale start to go up consistently. Once you see some weight gain just keep an eye on your fat gain. If you see it increasing rapidly then you can tweak down your calories a little. Personally if I was in your shoes I wouldn't worry about a little fat gain anyways. Once you put on some muscle that fat will come off very easily for you with just a bit of extra cardio and cleaner eating.