It's seeming like it will impossible to avoid vignetting and corner problems with my Epsilon at f/3.3 if I use a filter. Even if I thread a filter directly into the tilt plate, it seems the clear aperture of the filter would still not be enough. And no one makes a 50mm OSC filter...
We had an old gas engine shredder previously that was too heavy to move and needed constant maintenance. It is true that it could handle roots with soil, the occasional rock left it unfazed and odd shaped branches & twiggy growth went right through. The fuss outweighed the advantages though....