Here's the best picture of the coupler size, Joe.
I had to look at the car again to see what I did. I removed the cast on coupler box, filed the coupler pad a little, located the 905 and drilled a hole for the screw.
Mounted the 905 and clipped the end of the screw that protruded up through the end platform. After I filed the end and the platform was painted, you can't see the screw end
I added a BLMA air hose, but I see that I need to clip off the coupler trip pin.
Although the Z 905 is still a bit large, I use them only in certain places that I know will be seen and photographed. The front of E or F units and on cabooses.
Only occasionally have I had cars with Z scale couplers separate.
Greg O.
FYI - you need to be logged in to Trainboard to see this photo. -gfh