I decided to put the landing gear hydraulic dump valve inside the keel, where it will be accessed by opening a door just under the pilot’s right elbow. I plan to also put the main fuel shutoff knob here. This location is above the aileron torque tube, and should not interfere with other stuff in the keel.
An aluminum bracket was made to hold the valve itself, and a drilled aluminum backing plate was glassed onto the exterior wall of the keel to be a hard point for the valve.