When i first saw him playing years ago at a UGH concert he had a custom built by someone from Waipahu, Hawaii that just sang a sweet sound...can't remember makers full name but I think the last name was Young.
He used to play a Ko'olau too. If you mean like the one he used in the 'four string fury' on his channel, with the black curtain in the background, thats a spruce/rosewood ko'olau. Amazing sounding uke it was too!!