As far as I know our DOG is 1:1 scale. @spikeyxxx pointed out last month that our scale was slightly off to which I corrected in the 3rd iteration of the master file.
However I too was thrown off by the actual scale of the hydraulic lines as I modeled, especially when I found this video:

Which is a zoomed in shot of this part:

The fitting is way bigger than I estimated perceptually. However whenever I threw in a 6-foot human mannequin and placed his hand in the same spot, it didn’t feel that far off:

For the black lines (which seem thicker in photos) I’ve gone with 3/4″ diameter and for the metallic lines I’ve gone with 1/2″. What do you think @blanchsb?