Mike, I used a Long vertical gate shifter in our rear-engine modified roadster (the shifter is straight line, i.e., it is locked out of 3-4 until you move forward out of 2d, and then locks you out of 1-2), This let me put the shifter on the left side and avoid long, looping cables. I figured the simplicity of operation would resolve any potential confusion on the driver's part. I was right - 6 current records and three red hats. Plus, 1/4" Morse cables have worked fine.
I used a 4" center line on my gusset tubes; no complaints from tech.
vic