Ten degrees from horizontal is fine. 45 degrees for example, can be a problem, because when you are inverted, the fuel will fall to the front of the tank and the clunk in the back of the tank will draw air and the motor will quit.
But 10 degrees will not be a problem. Theoretically, when you are down to your last ounce of fuel and you fly inverted you may cause the engine to quit. but you should not fly around inverted when your tank is nearly empty.
If you always fly right-side up, you can put the tank at any angle as long as the back of the tank is level or lower than the front.