Pixhawk 2.1 mounting precision issue

Hello everyone.
Currently I’m building a fixed-wing a/c and wondering how precise Cube orientation should be. If the arrow of the controller does not point forward exactly (perhaps it might be off by 1-5 degree angle from being exactly forward facing), will it cause serious anomalies during flight?

Thank you.

Not really. Most humans can eyeball it well enough to see no problems. I would suggest getting it the best you can.