For the GMU22 Magnetometer My installation will integrate the Garmin standard mounting bracket. I first put the fuselage level as if in level flight and secured it. I want to install the Magnetometer on the second bulkhead aft of the cargo bay bulkhead. This is where most RV10 builders have had the least magnetic interference. I made backplate and mounted one side of the basic bracket. I left the other side loose so I could level it after the backplate is installed. I also made a gusset to attach to the lower aft side of the plate and plan to secure it to the upper skin rib. This will provide all the stability it needs. There is also a 3/4x3/4 angle running vertical on the backplate to fasten the gusset to. I removed the existing bulkhead rivets and installed the assembly. Running a very sensitive bubble level APP on my phone, I placed it on the bracket and moved the bracket until it was 0° all directions. This took a while. I then secured the back brace, rechecked and drilled it in place. After clecoing it I re-checked the level and found it to still be 0°. I plan to alumiprep, alodine and prime tomorrow.