Love seeing that SCL logo. I scratch build G 1:32 Stock and locomotives. something that may help your fabrication is a 3D printer. I print my couplers housings in ABS and some in PetG. You can use Fusion 360 or I find FreeCAD works great on the the two Part benches it provides. I had no cad background and it took about 3 hours before I was making precision train parts. Go College RU-vid, tons of FreeCAD vids out there. I grew up getting the crap scared out of me by those Black and Yellow SCL monster Locomotives in Florida. Sad part is I now live on an island with no rail of any kind. :) Thank for posting the video!
Joseph Lupinski added an important point. I used 906 kadee couplers because I have wide radius curved track. He uses 907 kadee couplers for body mount because his rr uses tighter radius curves. Keep this in mind when choosing your kadee product. 😉
Its annoying that makers dont use industry standard heights on couplings , it wouldny be so bad if there own make couplings actually worked, and the glue they use must be thinned down, a really fantastic product spoiled by economy ,, excellent advice from you cheers