A six foot blade would probably be ideal, certainly anything bigger could on occasion be too much. Lots of manufacturers out there and it won't take you long to see which look to be built better than the others. You really get what you pay for. One nice feature, in addition to being able to angle the blade, is also the ability to offset it. Some accomplish this by simply allowing the main beam to pivot (angle) right up close to the tractor 3-pt connection, while others have a sliding mechanism on the back of the blade. Stay away from the really cheap blades as they'll have no features, are typicaly made of very lightweight steel, in both the board as well as the bracing, and will likely bend the first time you hit anything solid, which you eventually will.