Found the Tracks hands being sold second-hand (hehe, puns) from a UK ebayer so bought them cos I figured I have Masterpiece Tracks coming anyways and if they don't work on Springer they can go on the figure they are meant for.
They actually fit surprisingly well. They're not an absolute 100percent perfect fit but much better than I expected and stay on well enough and are the right colour and a good size all round. They don't quite fit into car mode (but perhaps can be shaved then ever so slightly round the main hand part, I didn't want to try) and they don't stay gripped enough to hold a weapon (the weight of his gun or sword will make the hands open usually) but I see them as alternate hands (much like I have for various other figures like RoboCop, Batman, Superman and such) that I can use on him for expressive gestures and poses. And then switch back to his regular grippy hands easily when wanting him to hold a weapon (while the then currently unused hands go into the lil hobby container at the bottom of my shelves that contains all the hands and other bits for the superheroes I mentioned). I'm happy with these.
Mix n' match. Regular 'handle holding hand' on his right (our left) and the Tracks posable hand wrapping digits around the blade on his left (our right).