Many choices
The plans are just a guideline, and I have seen a zillion different set-ups in RV-4's. I built my own quadrant for my -4, and it was fairly easy. The location height and FOR-AFT need to be taken into consideration for comfort, and separation from the canopy latch handle. Also, keeping the knobs from being a catch hazard to your feet when getting in..my smoke button and tube handle on my DIY throttle are bad about that, though I'm used to it..I like the handle/vs knob feel. The bulkhead frame just forward of the throttle quadrant is often used as the retaining bracket for the cable retention, though I found mine needed to be forward to get the correct throw, and I had to fabricate a bracket for that.