Joe if you google Monro Tiller you should find my website, some info on there about each model. Tyres are obsolete, but are the same as used on Merry Tiller amongst other machine such as the smaller Barford Atom. 4 types of tine were available, knife which are straight, normal digging look like a sickle, hoeing L shaped and scuffling tines. I have owners manual as pdf file includes illustrated parts list.
Weak point is bottom of chain guard on miller drive, it wears through. Make sure you use a straight gear oil in the gearbox, not EP type. Lack of ground clearance can be an issue when working at maximum depth.