No experience of that Yamaha but when I started we had a Honda Fourtrak 350 and that pulled a big round bale of haylage up a reasonable slope no bother. When we replaced that one, the new Honda was 420cc. We did notice and appreciate the extra, but I’d still be happy with a 350 for a smallholding, unless you anticipate needing to pull a lot of weight up a steep slippy slope a lot.
That’s reminded me... When I was with ex-BH, I had another Honda 350. We had one long (more than 400m) steepening, gravelly slope with a tight turn on the steepest bit (at the top, of course) and a drain crossing the track too just below that point. It was a well-used tourist triai, so sometimes you’d have the added complication of walkers appearing on the track and not realising you
really didn’t want to have to stop or take avoiding action...
If I needed to bring more than one smallish ewe and her lambs up that track in the lambing trailer, I’d borrow his beast of a quad for that one