This mod works best if you have a scope rail on your marker and a spare old style spyder scope rail.
Find a pair of scope rings and attach it to your scope rail. Put a wooden dowel that will fit snuggly in your scope rings and cut it to the proper length of your scope rail. Slide the dowel into the scope rings and tighten them down onto the dowel. Get an old style spyder scope rail (as shown in picture) and cut it to fit between the scope rings IF NECESSAIRY, otherwise don't cut it. Take a small screw that is a little shorter than the width of the dowel and screw the old style spyder scope mount to the side of the dowel so that it looks like the picture on the right. Thats it! Now you can fit a scope onto your vertical feed marker.
NOTE: You might have to move the scope rings on the scope closer to the center to fit on the side mount.