Here's another image of the same type of sashing - this is more qst looking I think.

http://www.pinterest.com/pin/203647214374543391/

You might also consider paper piecing those narrow triangles. Might be easier than trying to determine & cut the proper angle.
In the second link you provided, the triangles are the same size as the ones used for the pinwheels. In the original, they are different sizes. The second one would probably be easier.

What nice sashings. Thanks, Jan, for your diagram.

This one is actually just 4patches with two HSTs, except for the intersections (pinwheel block).

what is PP'ed? And is this entire quilt made of tiny pieces or are the larger blocks a printed fabric to look like tiny pieces? I don't think I could live long enough to make a quilt with tiny tiny pieces. LOLLOL Plus, I am still scared of triangles. I will make a quilt someday with all tiny triangles, just to get over that fear. LOL

I would imagine that it is probably pieced like the Dear Jane blocks. You make the block pieces a little larger than trim them down to the proper size, Good Luck.

PP is abbreviation for Paper Piecing when the pattern is so complicated, it is easier to sew it to actual paper which have the design printed on the paper.

Very helpful!! I'm such a visual learner...
K

Check out Karen Sievert. She does the most marvelous things with prairie points, including putting them in the sashing. AND (above all) she makes it easy!!! Visit her at: www.theniftyneedle.com. Her books are published by Martingale.

When I looked at this photo, I noticed a horizontal join over the triangle in a couple. So i think the blocks look like a longer flying geese, with a strip added - like this - and a plain block either side. Hope I have helped.
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Why not take the advice on the Picassa post and reach out to the guild and see if the person who made the quilt is still there and would talk to you about the pattern?