I decided to mount the ELT aft of the baggage compartment on the side of the fuselage. I used two existing parallel J stringers to secure the whole thing. Some .040 sheet made up a doubler for the provided mounting bracket. That bracket has an additional clamping strap that wraps under it, lifting it away from the doubler plate. I added an .063 strip under the aft end of the bracket, match drilling two mounting screw holes to square up the bracket. Four 8/32 screws hold the doubler plate to each angle, attached to the J stringers with nut plates. I enlarged the ELT bracket mounting holes to accept 6/32 flush screws into 6/32 nutplates. All worked out real well. It was so humid that priming and painting was challenging. I baked the painted parts in 175 deg oven for 10 minutes to set up the paint. That worked fine. I wanted to eliminate any obstruction to rudder cables so I used flush rivets on the .063 strip. Rudder cable actually is totally clear of this whole mount, but better safe than sorry.
The mounting angles were cut from surplus panel part. 1 inch each side.
How it would look on side facing rudder cable.
Bracket mounting nutplates are no where near the rudder cable.