Something as simple as changing the location of a switch or a fuel selector could be deadly. It's important to know the differences thoroughly. There is also a question of fuel quantity. A mechanic offered him more fuel before the flight. When learning a new airplane, most pilots carry extra fuel aboard until they become accustomed to the individual aircraft's fuel usage.
Extra fuel is wisdom.
Each time the pilot reached for the fuel selector handle behind him, he inadvertently pushed the right rudder and the aircraft rolled and pitched up slightly, then down. Recovery would have been very difficult from low altitude. The element of unfamiliarity was a big player in this accident. Whatever the answers to these questions, it seems clear that this accident, like most, could have been easily prevented. There is nothing inherently dangerous about homebuilts or experimental aircraft and nothing inherently deadly about the fuel selector location in this one.