It can be helpful to get the free preview before ordering so you can see shapes and rough measurements. I have even compared a standard size against my personalized size against my ProFit size to see what's changing. I really like ProFit, but there are some measurements that I just use the system measurements for rather than my own. After trying more than a few pattern previews, I could see what was going to give me the proper result. Some of my measurements may have been a bit off as I had to have someone help me with them, so I figured that was probably causing at least part of the discrepancy I was seeing.