Personally I think you would have an easier job of putting those blocks together with a sashing & corner stones. Then a small border with the corner stone colour & a wider border the same colour as the sashings. You have some lovely blocks but they won't show to the best advantage without some definition between them. IMHO
If you are sure you don't want sashings, I think your layout of the blocks is fine, the way you have the 2 light ones placed looks balanced to me. Have fun!