Sashing and Pieced Setting Triangles

I decided on a diagonal layout for these blocks (plus a few more).
And sashing with cornerstones to give each block its own frame.
And pieced setting triangles just like the blocks, only a diagonal half.  You can see what I hope to make on the upper right and left sides between the first and second rows; one half-block at the top; and on the upper corners. 

Math is not my strength.  The math for pieced setting triangles without sashing isn't too difficult, but with sashing -- I don't know.  I understand that sashing changes the measurements for the setting triangles.  It's not that I can't calculate, it's more that I'm not sure which parts of the block need to measure differently than they do now.  I thank (but I'm not sure) that I extend only the pieces that will lay along the edge of the quilt so they extend further than if I were to cut a finished block in half.  I don't want to waste the time cutting, sewing, and trying out setting triangle sizes, but then I don't want to have them be the wrong size, either.

I searched google images for sashed pieced setting triangles and found not one with a pieced setting triangle.  I suppose there's a reason for that.  Maybe it's not possible to piece a setting triangle to use with sashing and have it look right in a quilt. 

We may see this quilt with chopped off points, or plain setting triangles, but I hope not.  Have you drafted your own setting triangles when using sashing?  Do you have any hints for me?

I think the sashing may be either a dark blue (with a hint of green -- what is that shade of blue called, anyway?) or dark brown.  I have several fabrics to try and then I'll have an idea what the blocks want. 

Exciting news for me:  a new grand-baby-boy is due in January!  I need to get working on a quilt for the little guy.  Decisions, decisions:  blocks, patterns, colors, layouts.  What fun!

I'm linking this post to
> Oh Scrap! at Quilting is More Fun than Housework
> WOW at Esther's Blog
> Building Blocks Tuesday at Quilter in the Closet
> Let's Bee Social #89 at Sew Fresh Quilts
Thank you, ladies, for arranging and hosting the link parties.

Also, I'm still working on an inspiration link party.  I hoped to be ready by this Sunday but we'll see.

Thanks for stopping by.
--Nancy.
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