[Tom Goldman]

There are a number of universal Neutral switches on the market that mount on the trans .

Glides are very easy to make your own switch for .
A split collar that fits the transmission selector shaft can be found at most good hardware stores.
By putting flat spots at the park and neutral positions on the collar ,a simple bracket can be made to mount a miniature lever style microswitch to line up with the collar.
You can find many different styles of lever microswitches on Amazon at very low prices , I'd stay with one made by Omron .