I'd do it similar to how I do the curved parts for the Dogwood Blossom quilt I'm working on. It's a combination of EPP and Piece-lique, Sharon Schamber's circle technique. (See here:
http://www.sewmuchlikemom.com/2013/0...ards-path.html )
Herewith an explanation of how I combined the two.
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1. The piece
2. Piece without seam allowances, cut from freezer paper, shiny side
up.
3. Press seam allowance over edge of freezer paper. It will stick. (This is something I do different than Sharon Schamber. She uses spray starch to glue it down. I think this works better.)
4. I pressed every other one so you can see that the inside curves need to be snipped so the seam allowance lies flat against the paper. This is important for when you stitch it.
5. Glue stick for sticking pieces together in the next step.
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6. Place outer and inner pieces on template as shown. Apply glue stick to seam allowances on back of center piece. (I used blue pieces so it would show up better, then sewed in the white piece that actually goes there, in case the change of color is confusing for anyone.)
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7. Press to dry glue stick. Pieces should be well attached to each other.
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8. Slide tool between fabric and freezer paper to separate them. Using a sharp pencil, mark along stitching line. (This is optional. I do it so I know I'm stitching where I want to be. For more advanced sewists, this step can probably be skipped.) See the little pencil lines? After you draw the lines, remove the freezer paper.
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9. Sew the parts together. I use a zipper foot instead of a 1/4" foot because it is easier for me to see what I am doing. (And truthfully because I'm not that experienced at piecing curve. I could just as easily title this "Every crutch I know for piecing curves!" Lol, keepin' it real.) I have the piece pulled away from the foot to show you the pencil line, that's not how I sew.
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10. This shows the piece where it would go in the block.
I would have done it with your sketch, but my printer is out of magenta and the one we ordered said it would fit, but it was all lies, lies, lies. So, printer is a doorstop. Maybe next week...
Anyway, I hope this is helpful and the pictures aren't too gigantic and weird.