Jacob rug on the Ashford 4 shaft loom

Kate told me that to weave stripes that never fail to please the eye all I need to do is add the width of the previous two stripes together with a constant number in between. In this twill rug I started off with 
10" dark jacob 
1/2 " mixed, 
1" dark jacob, 
1" mixed, 
1" dark, 
1.5" mixed, 
1 dark jacob, 
2.5" mixed. 
1 dark, 
4" mixed . What appears to be a warp thread is my measuring thread, knotted every 10" so I know when I have got to the middle. when I get there I shall do a 6" section of dark then reverse the sequence.