KD makes a wide range of couplers in “G” and #1 scale, The G scale are basically for, well G scale the #1’s are made for 1/32 scale. They have a large selection of specialty couplers made for specific engines like Bachmann Shay or Bachmann Heisler in either scale.
As has been stated body mount is best for operation and they look right. As for Garden Railroading Urban Legend #21, Yes #1 couplers have a smaller face area so they are less tolerant of vertical differences in track work. I have ran them for over 20 years with no problems.
What are you modeling? Standard gauge, than use the G scale ones if they suit your eye. Narrow gauge? the #1 couplers are spot on scale wise (in 1:20 scale) for most narrow gauge couplers that were/are used in the real world. Most all Narrow gauge railroads used a 3/4 size coupler except Colorado, they used the full size ones.
If you decide to go with KD, no matter which size, buy their height gauge and use it!!! Standardize the coupler height on all your cars and locomotives, no matter what height you decide on, use it on all rolling stock no matter how much work it takes to convert. A few hours spent standardizing saves years of grief with poor operations.
Of course this is just my opinion, but opinions is what you asked for, right(https://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-foot-in-mouth.gif)
Rick