I have basically the same set up as you and would not change a thing . works great for snow and even better for ice removal on a driveway.Here's how I did mine. Everything is welded so it has downforce. It's been behind a 270 Deere for two seasons and has had the snot beat out of it and it's still holding up fine. No repairs yet since I put it together. In total, I have about $200 in this plow.
If I were to build another, which I will someday, I would have put some more pitch on the mounting plate. Have it tilting forward a bit so all you have to do is raise and lower the blade with one pedal.