Grand gorillas’ are not gorilla-like at all except for their walk (biped but walk on all fours like a gorilla, with long arms, powerful builds).  They look more like a protoceratops if it had a body more like gorilla, with thick iridescent fur, and a heavy lion-like mane on the chest.  Like a protoceratops they have a flange that comes up behind their head.  This is both protective but also shows dominance, with males having one twice the size as females, and older males a little larger still.   This gives them a very regal appearance hence the name, grand gorillas.  About 4′ to top of head (6′ if standing on rear legs), add another foot for male head flange.  They don’t wear clothes, but hats, belts, holsters and shoulder sashes instead.