The slider canopy moving back and forth shouldn't be an issue - it's not likely you'll be flying (and relying on your ADAHRS unit) with the canopy open - but any metal (magnetic) objects in the cargo back, as well as ski's, rifles, or elevator servo motor, could interact with it.
Put it back in the tail just forward of the empennage fairing, life is good. The only ferrous material back there are the bolts in the elevator and and rudder sections, and their movement is minor in flight. The seat belt cables are just forward of there, but they don't move.

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Greg Niehues - SEL, IFR, Repairman Cert.
Garden City, TX
VAF 2020 dues paid 
N16GN flying 700 hrs and counting; IO360, SDS, WWRV200, Dynon HDX, 430W
Built an off-plan RV9A with too much fuel and too much HP. Should drop dead any minute now.