Provided the hole in the front screen is 50mm in diameter maximum you are fine. Where you place it is important as you ideally want it in line with the engine head but you also want to have clear and easy access to the fuel tank for simpler refueling in those mains finals.
What I normally do is cut the whole with the center right on the point 25mm inwards towards the tank from the center line of the engine head. This gives clear air to the head still and allows you clearer access to the tank.
You dont want to cut the hole on beyond the roof line as this really effects the air flow and aerodynamics. What I do is cut the hole so that the upper most part of the cut out is level with the top of the engine head or just slightly above it without going any closer to the roofline than 10mm.
Hope this helps.