I pulled this from my building photos archives. Not sure if this is Gretz or ?? and not sure if it is RV-6 or not, cable path does not look right.
In my case, I've been planning on using an RV-10 trim cable and mounting in tail cone appropriately.
Found this text description on another site:
"The Gretz Aero method of mounting the electric Ray Allen (formerly MAC) servo elevator trim is VERY EASY to install. It does not add the weight of the servo to the elevator, which has to be balanced out with lead. It moves the weight of the servo forward to the leading edge of the horizontal stabilizer. It saves overall weight. This alternative method places the servo on the rear fuselage deck, between the horizontal stabilizer and the vertical stabilizer and is covered over with the fiberglass fairing provided with the fuselage kit. There are few parts needed for the installation. The hard to find and get parts are made available to you by Gretz Aero in one inexpensive package.
Installation kits consist of:
New push/pull cable
Weldment like wd-415 (not a Van�s made part)
Two each special clevis for servo end of cable and trim tab control horn end.
Bag of mounting hardware needed for installation
Instructions for installation
This kit is best utilized installed on a RV-6/RV-6A, RV-4
RV-7/7A, RV-8/8A, and RV-9A, originally built with a manual trim. "