So I grabbed a few sheets of 220 grit sand paper and placed them on a big piece of glass and started moving the spacer around in a figure 8 motion and some of the spacer was being sanded and some of it wasn't being sanded. I'm guessing the spots that were being sanded were the high spots?
Anyways I moved it around in a figure 8 motion a few times. Do you think it is straight enough now? I don't have a straight edge but I do have a ruler, whats the best way to tell if it's straight after sanding it in a figure 8 motion?