Permitted compass elevation angle

Hello,

I’d like to ask what angle is permitted to mount the compass in the plane. I’ve read that it should be horizontal but this does not work out in my case.

I currently building an ARWingPro and found out that the intended GPS mount in the rear section has a small elevation angle upwards, so my Holybro M10 GPS+Compass is pointing about 10deg upwards.

I also see problems in the location with the ESC that ~4cm below it, some magnetic cover holders 6-8cm in the area, so I’m evaluation if it’s any good to mount the GPS+Compass in the front where the center camera is supposed to be.