I really think that the border is too wide. Use the fibonacci number formula to determine the width of the border that is most pleasing. That is : divide the width of the smaller blocks by 1.6 and then keep dividing answer by by 1.6.
A nine inch block:
9/1.6=5 5/8; 5.625/1.6=3.5; 3.5/1.6=2.2 (round up to 2.25) etc. The answers 5.625, 3.5, 2.25 will provide border that is proportional and give the most pleasing effect. This formula works well for of deciding width of sashing and all borders.