I've done the 60 degree 2" stars EPP.
I have the new Brimfield block by paperpeices.com that i will start on new years day. it has curves in EPP.
my friend showed me how to do the opposing curves the easy way. put on the table and tape them togethere with scotch tape on the right side. then pick up and stitch together on the back. the tape keeps the shapes together and with an accurate seam.