Jose,
Would I be correct in assuming that you have replaced one or both of the panels that the top side plates secure to? Is the top installed on the frame, and do you have the windshield installed? I am asking because how you fit the frame may depend on what stage of assembly you are in. If you can put the frame up and temporarily clamp the mount plates in their approximate positions you can move them around a bit to achieve the best fit. Do you have the old panels that have been replaced? You could take measurements off those and probably be pretty close. I was able to drill out the one side panel I replaced by measuring what I had removed and putting the frame up without the top fabric installed. The original holes were drilled oversized to allow some adjustment before tightenng the screws. If you have replaced both panels and have no screw holes, let me know and I can give you some rough measurements.