I've got a Mitsubishi/Satoh Buck S470D 4wd tractor, 18.5 hp/ 16.5 hp at the pto. Most seem to recommend a 48", some say a 60" would work. I've got a hilly, mostly open, 2 acres to mow. Currently using a GT2550 Cub Cadet, 50" deck. Seems like the extra 6" would be worth the roughly $500 vs...