[doublepost=1475671017][/doublepost]I have installed cDock in Sierra. Could not get transparancy.
Made a transparent picture in PS, size 300 x 191 pixels/inch, dpi 150 pixels/inch and named it Trans and saved it as .png
Copied Trans.png in map: user/Library/Application Support/cDock/Themes/Transparent.
I have a tranparent dock now.
The cDock preferences window is now pure white and a bit changed, but no problem
Good Luck
Regards, Roeland