Just to clarify:

I have a bunch of higher end Simplex derailers an all that are intended for attachment directly to a dropout use a bolt through the back of the hanger. In other words, the pivot bolt is drilled and tapped for a bolt. Those that are intended for use with a claw have a pivot bolt that takes a nut. The bolted derailers also have a tabbed washer that is not present on the nutted version, so they are not interchangeable.

I replace my Simplex pulleys with Bullseyes. I use two of ithe supplied 6mm washers on each side of the pulleys.

As soon as it gets warmer, I'm going to go out in the garage and put some Bullseyes on the SX610 on my Jeunet. The came in a bag of parts I bought for $17. There was also two sets of Stronglight 93 dust caps in the bag,so it was a bargain. I made an arbor for the pulleys and chucked them in my drill press so I could polish them. They're much too pretty for my beater Jeunet.