Charles , Williams prop controller pickup is great. I've been using them since about 2000. Keeps the pickup contacts behind the gearbox out of the weather. Much cleaner looking than the stock pickup Ivo includes. Nice item. Very simple but ingenious.
Only drawback is if someone is running a Rotax vacuum pump on their engine I don't think it can be used. Murle is always happy to assist over the phone if you need him. I don't think I've seen the instructions so can't help you there. Murles' phone number is 602-978-0553.
P.S. Our favorite aircraft kit manufacturer also carries this style Ivo prop. controller in their new parts catalog.