The only "intended" use for a blade in the front mount position, is pushing snow. It is meant to drop to a solid surface, ride on the shoes, and push snow. The blade is not designed to maintain grade while in the snow pushing position, and it does not have enough leverage to keep from digging or climbing. This is why snow blades have shoes on them, to allow the snow to "load" the blade, keeping it on the pavement, pushing on the shoes, and push to clear the snow. This will also work on gravel drives, but you have to set the shoes deeper in order to prevent pushing gravel everywhere.
If you want to grade things, you need to mount the blade in the mid / belly mount position. In this position, the lift rod is directly up/down, directly above the blade, and you now have excellent depth control. Matter of fact, the manual will tell you to remove the shoes from the blade, so that you can dig with the blade mounted in the belly position. I can tell you that you can hold grade to within 1 inch with the blade mounted in the belly position. I graded out an acre of topsoil this way, and I was able to hit every grade mark perfectly. You couldn't do it if you tried with the blade in the front position, because all it wants to do is climb or dig, as it was designed to do in that position.
1951 Farmall Cub, Cub Cadets 102, 104, 1811, 1864, Simplicity Legacy XL 4x4 Diesel with FEL, 60" mower, 50" Tiller