Only problem I see is how far out behind the tractor the weight is. Not sure but is it going to reduce traction on the front tires? As far as the welds, make sure your wire speed is high enough when welding heavy steel. If it sputters and arc stops occasionally your wire speed is too low. I'm still learning with my welder but I know if you can get an even 'sizzle' sound, like bacon frying, your wire speed is high enough and you'll get good penetration.
EDIT: Just remembered something. My cousin calls them 'gorilla welds', ugly as a gorilla but just as strong! I've made quite a few of them. Once you get the wire speed right your welds will smooth out a lot. If you lose the arc because the speed is to low the metal cools and won't flow smoothly. Go buy a few junks of steel at TSC, cut them into small pieces and practice.
Edited by HankS, January 21, 2013 - 07:42 PM.