I've left the backhoe on as a counterweight this year ... all I had. No doubt the weight helps a great deal, but I'm still working towards something more compact. Almost took out the garage the other day /forums/images/graemlins/blush.gif.
I've found that weight it OK as long as you're on snow. We had a bad batch of feezing rain and there was ice everywhere. I needed chains then. Luckily I borrowed some from a friend. Great heavy ones with rings like a skidder. Only got one on (still can't get the other power adjust wheel to free up so I can move it out to give clearance) but it made a night and day difference. Had to brake the other wheel now and then (no diff lock).
Thanks for posting the pictures, it's sure a nice compact, simple design. Andrew