I almost forgot about my tip today!
Today I will go over how I size my paper piecings in the SCAL program (you could probably use the same principles in your cutting program). I don't care for lots of math, so I came up with my own method.
First I visualize the size of the area I have to fill on my layout. Then I open up the pattern file I want to use. Using the squares on the mat (each square = 1 inch) I add the size of the body up in my head (such as 2 inches on the legs, 3 for the body, 1 for the head etc...). If this is too large or too small, I size it up or down a little by pulling the corner (always lock the proportions first!)
Sometimes I will 'ungroup' the piecing and put it together on the screen to see the size better.
Now, say I am using a set of patterns and I want them all to match. If I am using a set of bears, once I have the first one sized and cut. I delete all the pieces except for the head. I pull the head off the cutting mat and bring in the next bear. I pull the old head over and size the new one to match it.
This may not be the easiest way to do it, but it works for me. Happy Scrapping!