A couple of thoughts. If it's the picture I saw, and your problem is that the points don't match, perhaps you could add some sashing between each block? Then the point matching won't be so important. You might still lose a few points, depending how you trimmed, but it won't be as obvious.
For you trimming issues - pictures would help, but I think the problem was that as you said, you can't center a block. Rather than trying to do that, you should check when you are trimming that all the points you expect to have when done are exactly 1/4" from your trim line. That should keep everything square and easier to line up when you are ready to assemble.