I think they all look nice once blocked and flat. I have managed to block all the squares to more or less 20cm x 20cm, but some with more difficulty than others. Clue 4 would have been quite a stretch to 20 cm if I hadn't added the extra 4 rows to each square. The designer probably wanted a lacier appearance but I'm not sure that this would look good against the heavier squares. I much prefer the fourth pattern to clue 3, which I found rather heavy looking with the thick garter stitch bands. At the moment I am a little worried about clue 3 as it does seem different to the others in size and thickness. Clue 3 gave the largest finished squares before blocking.
I tend to favour a more uniform appearance and ultimate thickness. I am concerned that the squares will distort once sewn together and a flat blanket would not be possible if there has been over vigorous blocking of some squares against others. Hoping that they will all look good once sewn up into the final blanket.