Send a pic of the chopper couplers! I love the idea of different couplers apart from AAR couplers.
Not to go too far off topic but I have a 4-4-0 that I am planning on using some Link and pin couplers on. Just to have something different.
There is also a guy who is making Russian outline HO scale, having the proper SA3 couplers for that would be cool too. Just can't stand Kadee couplers anymore.
I agree on the Kadee coupler looks. At 73% the H0 Sargents are fiddly close for 3/4 size in S. For a type D just file a bit on the knuckle.
I use AAR coupler height and Choppers from New Zealand for my Sn2 Gilpin in the Bitterroots. I use H0 Sergents converted to Type D for my Sn3.5. And, I will use S Sergents for my wide (std) gauge S. As I do 1923 I may convert them to Ds also.
Talmadge C 'TC' Carr
Sn42 and Hn42 somewhere in the wilds of the Pacific Northwest