Perhaps the question is better asked in the FPGA or Microcomputer section? Move the question, don't cross post. I think equal impedance / length lines seem to be most important and I sometimes see resistors of around 22 ohms in series. I was told they help stop reflections. If laid out with care (I always said "It just looks right") with a ground layer in between you should be fine. After years of trouble shooting boards that have no bad components but still give random faults you can sort of visually see the difference between a well laid out board and a board done by someone who was clueless about fast high speed signal routing. 'Then the stories start!!' Cheers mate, best wishes.