We failed in the initial interference check with our magnetometer in the right wing. I think we saw ~130% of the limit on the Garmin. We moved it forward ~8 inches and passed the test at ~40% of the limit. A small change in the distance to the counterweight made a huge difference in the interference level. I think as long as you bias forward on the rib you'll be ok.
For reference, our original install had the magnetometer just after of the conduit in the pic. After moving it to the forward side of the conduit it worked fine.