It appears that the score function and the Ideal SS tool have different ideas about what makes a great helix. If you run Idealize SS on a helix, and then shake and wiggle it (assuming it has at least one end free), tokens pointed out to me that wiggle will make the helix shorter and fatter. The dots on the rama map will move down a little bit. Which is right, the "ideal" shape, or the higher-scoring one that wiggle likes?
I have also noticed, when using the rama map to make design puzzles, that my helices are always 17 or 16 residues long (or 21 if I make longer sheets). That makes the number of turns come out right for having the attached sheets fall in a plane. The helices in the Koga & Koga paper are all 18 or 14 residues long. If the curl of the helices is the same, it should take the same number of segments to get the right number of turns. If we are using the ideal loops they discovered for their paper to connect helices to sheets, why would our helices not be the same length?