I've just gone to the Marcia Hohn site and found the butterfly you are trying to sew. Check out the template no. 1 that she provided. You will see that it is in 4 parts. The long narrow section on the right is the body of the butterfly, so you don't have to worry about measuring or cutting out extra pieces for the body.
When I paper piece, I simply cut out a piece of fabric that I know will cover the section of the pattern that I am sewing. After the seam is sewn, then I can measure seam allowances and cut off the extra fabric. Make sense? Then you do not have to worry about templates or anything else. Neither do you have to worry about grain or anything else that can influence seams since you are sewing on a stabelizing paper pattern.
After the whole piece is sewn, then simply tear the paper off the back and the section is ready to sew to other sections.
Marcia is quite meticulous with her patterns and directions. Trust her. It will come out right in the end.