My longez had the fuel valve mounted in the hell hole. It was actuated with a torque tube (as opposed to the little rod that the Varieze used/uses). Actuation was very solid feeling. Mounting location near my right shoulder/elbow was not a problem.
My Cozy has the standard valve mounting location (right elbow). However, I do have a both selection that I run mostly---and do have the ability to run right or left in the event that I need to tank isolate.
John Denver's biggest 2 problems were:
1. Failure to realize he was too low on gas during preflight---even though he looked at and acknowledged the tank amounts.
2. Failure to realize that he was not going to restart the engine, failure to suck up his fate, and failure to execute a nice landing in the water. AFAIK, 100% of EZ water landings (pilots executing a good landing in the water as opposed to an uncontrolled crash) have had 0 deaths.
The fuel valve set up, the extra cusions behind his back, and rudder pedals that were that were not yet adjusted for him---were all contributing factors for not restarting the engine. But if number 1 (above) was taken care of, there would have been no reason for number 2. And if he executed a good landing----he would be out a Longez---but he would have survived.
The John Denver story is not a Longez story----it is a pilot headwork story. Pilots running out of gas is one of the worst headwork items. At almost every fly-in/airshow, people ask if my airplane is the kind that John Denver died in----and then they more or less want to know how I feel flying an airplane that has those kind of problems. Of course, I reset their thinking----any pilot can run any plane out of gas---and he could have survived it.