looking by his results i'd call it more a 'burner' or charcoal maker then roaster! would be hard to get repeatable roasts id think.
Id really like my Behmor that Andy sells via beanbay and comes shipped with 2.5kg of greens.
second hand behmor's seen to come up in for sale section of forum from time to time or maybe try a WTB ad.
Or if want to try on the cheap get a popcorn popper (heaps on info on here about roasting with one) as plenty of people use them well.
Good luck and hope the rabbit hole isn't too deep!