Hi oh I know this kind of problem when I was in the starting holes for layouting :) For mounting breadboard-PCBs on the plate I made a breadboard-template (Holes 1mm Diameter, 2,54mm between the hole-middlepoints !) in my layout, so I can see how the holes fit onto it. Then I print the part of the layout with the breadboard to compare it with the stuffed, not soldered PCB Maybe this picture can explain what i want to say, sorry for my english :) Regards