Mike,
A couple of years ago, the gap for open segments was calculated as a percentage of the segment edge length. You are probably looking at an old tutorial that showed a percentage of something around 20%. When I added the SegEasy plates, though, the gap on them was measured in degrees instead of a percentage. So I changed the gap to match the SegEasy plates. One method is not better than another, but it only made sense for the software to be consistent with the plates I was now selling.
However, I also made it possible for you to override this. At the front of the 'gap' line is a checkbox and if it is checked (it is by default), it automatically calculates the gap by the degrees specified. If you uncheck it, though, you get to pick whatever opening you like. You do this by putting a value in the 'Vertical Spacer' field in the left column. If you wanted the opening to be exactly the same for each row, you would just enter the same value in every row. You can have every row be different, though, so the bottom line is that you can have it any way you want it.
Please let me know if you have any questions on this.
Lloyd