Poor interpretation of online descriptions and lack of guidebook means that what I ended up doing wasn't what I thought it was, and I can't find any mention of it anywhere - don't know if this has been done before. Seemed fairly logical if you don't like dynos.
From the right-hand jug of the Tree-tastic dyno, move up to the small sloping pocket above, and use it to rock up left to the same finishing flattie. Not really sure about the grade, could be pretty morpho - probably have to jump a bit if you're short.