OK Honda doesn't make a 600 anything, so, are you sure this is what your atv is?
they made a 650 and a 680 in the rincon?
I would recommend a 60 inch blade, as you need to remember that when you angle the blade all the way, it will only cover about 54 inches of a clear path as you plow, a smaller blade on a full sized atv can lead to snow either NOT being cleared of the tire path when at full angle, or snow rolling back into the path being cleared, causing less traction for your atv
90% of folks that add a plow to a Rincon I know, , end up adding HD spring for the front end to help hold the weight of the plow better, as the Rincon series ATV was more of a trail atv than a work ATV, so they have slightly softer springs to give a better ride(Foremans and Rubicon's were the more work line up of atv's for honda, and still are, and none of them were ever a 600 too)
front mount plows are faster on /off, more user friendly, but place more weight on the front end than a mid mount and can lead to added wear and tear on your front end parts, they cost more too
Mid mounts are the strongest set up made, lower price and more work to take off and on, but not bad once you get used to them, you will loose ground clearance with a mid mount in OFF season, or when plowing, if you leave the mount on bottom of your atv
Not a big deal to most, but to some it matters
I have a moose mid mount for 17 yrs now, been bullet proof and I abuse the crap out of it, plowing snow, dirt gravel and logs and you name it, all yr round
I prefer a winch to lift the blade over a hand lift, too!
hand lifts work well, but grow old fast IMO !