I should clarify a bit more- yes, you can turn the P4 male shirt into a shirt for Don, but it takes more work than you think. Imagine the P4 shirt as a solid rubber block. It's got bones in it that are the same size as the P4 guy, so you can put it over him and it will move the same. To make it work in the P5 cloth room, you'll need to basically hollow out the shirt and pull out the bones, then squeeze Don inside it. (Most of the tutorials you're referring to tell you how to do this.) The cloth room will then take the rubber and transform it into silk, so it lays realistically against Don's skin. The main advantages of dynamic clothing in P5, apart from looking way more realistic than conforming figures, are that they're slightly easier to make, and that, since they have no bones, they're a lot easier to resize to fit other figures (unlike conforming clothes for the P4 fem, or Vicki, or Judy).