I traced my BSWW and used that as the pattern for a few T&T diapers, and then made adustments based on how the dipes I made fit my son. I ended up shortening the length, lengthening the back tabs, and narrowing the crotch a bit to come up with a great pattern that I love. So to answer your question, yes you can trace a wrap and use that as the basis of your pattern. My kid is quite chunky and the diapers I made fit him very well, so if you've got a skinny kid, you might want to make the pattern smaller right from the beginning to avoid a really loose fit. Good luck!