Glad I could help!

After laying the quilt out on my bed with the one rail fence that I have, I love it! Hopefully I can follow your instructions easily enough - it just looks so right!!

And I agree with doing it as a square adding the strips to the top and bottom to make it the right size. I'm going to use the green check to do that, what would the sizes be for that?

I have learned over the years to always KEEP IT SIMPLE. You can KEEP ALL your blocks. Just do a little tweaking ONLY to the outside border which should get you to a 19" x 15" finished size for BOTH blocks. Finished size refers to the size of the block when it has been sewn in the quilt. Unfinished means that the seam allowance are included with the dimension. Hope you understand that.

You need to add an inch to both the top and bottom border (to add 2" in length) of the Sunflower 17" x 15" block so that the new measurement will be 19" X 15". Thus the proportions are NOW a difference of 4" between the length and the width (that happens to be the size of your rail fence block) If you ONLY remove the top and bottom border and replace it with the same fabric but cut the border strip 2.5". Or you could choose to just add another 1" border strip to the top and the bottom to end up with a 19 x 15 inch finished block. REMEMBER, this is NOT including seam allowance.

With your rail fence, 3 block across and 4 down, that give you a finished size block of 12 x 16 inches. Then you can add a 2" cut border strip to each side of the block. That will add 3" to the length and width of the block, The block should be 19" x 15" finished. (19.5 x 15.5" unfinished)

Another hint is to make your final outside border a little bigger. That way, if your blocks are short you can cut all your blocks down to the exact unfinished size of 19.5: x 15.5". Hope this helps. PM me if you have any further questions. GOOD LUCK and HANG IN THERE !!

All you need to do is add an inch (finished) strip of the green check to the top and bottom, so cut your strips at 1 1/2" wide.

Since you are not trying to make it 19" x 15", none of this applies.