Hodgy, congrats on the b7800 - I have one as well, think mine is an 07 I've had it 3 years now and love it.
I too looked at adding weights but was steered away from that decision by a kubota mechanic who said it's possible to cause damage to the rear axle if spinning the rears with wheel weights.
So I added 220 lbs of -40 windshield washer fluid to each rear tire. It's made a huge difference when snowblowing on steep driveways.
My neighbor's driveway is even steeper than mine and any wet snow I could only get up halfway even in low and 4 wheel drive. Since filling the tires I can go up in 2 wd most of the time.
Greater stability as well.
Are they heavy to handle? Yes, but not that bad if you keep them close to the floor when taking them off and on. I'm 62 and have had them on and off myself.
I have the owners and service manuals for the B7800 as well if you're interested.
Keith