All my Kaleidoscope blocks have been trimmed down to 5 1/2 inches, everything lines up perfectly, I can see the secondary circular pattern emerging, and I think it is safe to say this endangered quilt has been saved! Trimming things makes the quilt smaller, obviously, so I plan to add at least two, maybe four more rows of nine blocks.
I am using a ruler called the Kaleidoscope Smart Plate. It is actually an excellent tool. However, the instructions were a bit confusing to me (not necessarily the designer's fault). The premise of the tool is that instead of cutting out isosoles triangles and sewing the wedges together, you make pinwheel blocks, trim them to size, then use the ruler to cut your octogon shapes.
Notice that at the top and right of the photo, you can trim the white fabric into kind of a kite shape. This saves you from having to sew on corner triangles. Very clever, really. The print fabric gets trimmed straight off, leaving you with a block that looks like this:
This is the eight piece block. You also need to make twelve piece blocks, that do get corner triangles sewn on.
So, here is where I went wrong.
1). I did not trim my pinwheel blocks down to the correct size.
2). When I sewed the corner squares on, I assumed I was using the draw line/sew on line/flip the corner up method. What I should have done is cut the squares once diagonally and just sew the triangles on the block to form corners. Not doing that caused me to have seam allowances on the twelve piece blocks that were 1/4" off. As someone pointed out, my corner triangles were way too large.
See? The block above is done right, the block below on the right has corner triangles that are too big.
I will talk more about the Kaleidoscope Smart Plate ruler, but right now I am just going to go do a happy dance that this problem was sorted out, thanks to all my wonderful math savvy, non-spatially challenged readers who gave me advice!