Tips For Leveling a Delta?

I have been trying endless to no avail to level my Rostock Max v2. I can get prints that stay within the center to print really well but anything on the edges and it does not. Spend my whole entire day yesterday trying out various things to get my FSR sensors to trigger more evenly across all points but still nothing. Link below is an image with a spiral showing where I am having issues getting the bed leveled. The area between the Z and Y towers, and basically anything in the center. They are too close to the nozzle so that is why you do not see any filament.http://ift.tt/20DSMPN: Adding more information. I am running a Duet board running DC42 (RepRap fork), and using FSR sensors mounted under my heated bed with my nozzle acting as the probe. http://ift.tt/1YZ8B2R