I wonder if they'd sell just the tread-pontoons; I'd like detail on the inside to match. (Thanks for the second piccie, by the by; I didn't realize it was open 'twixt treads up to the 'cabin'.
I suppose a clever and talented fellow could detail the insides well enough, but I'm thinking, if not too dear, cutting a 'cap' from the outsides of the spare tread to cover the insides of the main tread bodies would seem simple enough. Except, the seams wouldn't necessarily be so simple.
Doug