Saturday, with this thread in mind, I used this target
http://www.targetz.com/targetzlib/10013.pdfto shoot a couple of 5 round groups at the end of the day. The scope was a Meopta Meopro 3-9x42 with their version of a duplex reticle. I shot one group on 4x and one group on 3x, both at 100 yards. The sight picture was good even with the center dot obscured, I just laid the reticle lines evenly between the big blocks. I'll measure them tonight, but for now I'll say if you're using the right target then shooting well under moa with 4x isn't a problem.