I'm not a huge fan of making your first cycle a cut. Reason being, you have such great potential to grow on that first cycle and growth can only happen when you're getting a surplus of cals. Yes you can grow new muscle while cutting fat, up to a point, but that growth may be limited if you want to get very lean. There comes a point thats different for everyone, where you really can't get any leaner without really pushing...lowering food and doing more cardio. For me, its at about 6%. At that point, it's going to be impossible to add more mass.
But just to answer your question, as I said, yes. Its all going to come down to your diet. You'll need to strike the balance between diet and cardio, plus not over doing the t3, in order to gain while losing fat. Plus, as I said, the leaner you get, the harder it will be to strike that balance. There isnt a formula I can give you, as everyone is different. I will say though, that your protein should remain HIGH through the whole diet and your fat loss should come from manipulation of carbs and fats.
Be sure to use an AI to control estrogen and help fat loss. Also be sure to run PCT, 2 wks after your last injection