The reason I chose to go with the straight blade cause after seeing SonnieP's (TBN member) pictures of how well his duragrader performed. I decided to mounted them straight. The unit can be scaled down if that is what is needed. The reason I chose the 7 ft model was cause UPS will not deliver anything bigger than 7 ft. Anything bigger than 7 ft, they would have to be shipped on a semi truck which was a whole lot more for shipping. The 7 ft model covers my tractors tracks and it allows me to get up closer to what ever I'm working on (fence line for example). The blades I am using are for a RB84 woods grader blade (back blade is what most call them). The blades are flat on the back side and round on the front side. This allows the dirt or gravel rocks to roll on the blade. I had thought about making a removable shield behind the last blade to help move more dirt or gravel rock. Glade I didn't cause adjusting the angle of the front blade will cause it to cut allot of dirt and will build up in front of the blade allowing you to drag more. When the front blade cutts allot of dirt, your going to need allot of horsepower from the tractor. Mine is 48 horse power (TC48DA) and there was a few times I had to dump some of the load cause the tractor would spin. Keep in mind how much dirt weighs if it has some moisture in it. Word of advise to those that are going to build one. Once people find out that you built one or see you using it. They will want you to do there driveway or some type of landscaping for them. Been there and done that. I've had mine built for a month now, and I have done several peoples places. You can make allot of money using this type of implement. I finally got to take my blades off mine yesterday so that I could wash it down and put some paint on it. If I get a chance today, I'll take a few pictures of it while it is still clean.