Sounds like a fun project. Sorry i dont have a drawing for the plate. i just drew mine out myself and cut it out of a square pice of 3/16" aluminum plate. i cut out the center with a hole saw. I dont have the dimensions but i can get them tommorow maybee.

On the XYZignition. Mine failed this weekend causing a very frustating weekend. if you do go with the xyz or any electronic ignition for that matter I would keep all your stock parts and keep them with you as aback upjust in case your electronic decides to poop out at a flying event. I wish i had mine with me i would have taken all the sensor parts off left the battery and ignition box in and wired the plug lead out of the way, installed stock ignition and kept on a flying. Honestly you really dont need the electronic and there really isnt much advantage to it. I dont think im gona bother replacing mine.

Oh yea i think mine failed cause it got gas soaked from a fuel leak in the fuel line.