I have three blocks put together so far. These are all from the same charm pack. I noticed one block is larger than the other two, maybe about 1/8" or 1/16". I plan on setting them into a white background. Do I need to trim all the pinwhell blocks to the exact same size? The other question....what is the trick to exactly matching the points. The three I've completed are fine. But the one I was working on a little bit ago is giving me fits!