I always use 2 1/8 forward of the hole but my mounts are based on skymangs so they are 3 3/4 wide, so thats the same as 2 1/4 forward of the oval hole, unless my math is wonky.
I also cut my body mount holes a little larger than the mount for some small wiggle room they are centered on this truck currently though.
IMG_0681 by
Joe Doh, on Flickr
I chucked a fender on to see how my alignment is, its important to "tuck" the rear of the fender into the recess on the cab, it will almost snap to it. also it is important to level the bottom style line of the fender so it doesnt point up or down.
here is my (fender only)! alignment.
IMG_0682 by
Joe Doh, on Flickr
this truck has the Z85 rpo which is the high riding suspension, bigger coils in the front and an extra leaf in the back. so my tire will go back slightly with a drop coil too.
so make sure your fender style line is mostly level with the frame, it could be you have the front pointing down a little.