Hi. I don't know if you've already taken care of your question about wiring for the Sanken and the EW100s. I'm guessing, maybe you are talking about creating an adapter cable? In case not, just an fyi headsup, you can get (or make your own) an adapter cable, with a locking mechanism/
3.mm male connector on one end (for the Sennheiser transmitter), and a Lemo tr5f 5-pin on the other cable end (for the Sanken COS lav mic)... a Lemo tr5f IF your Sanken lav has been wired for Lectrosonics wirelesses, that is!
If you end up not being able to do yourself, you can get cables made by Trew Audio here in the U.S. (and a local audio vendor here in the DC-area). They just need to know what type of Sanken lav, and of course, when you purchased it. They usually prefer you send the mic to them, so that they can use it to make sure the adapter cable is created successfully and that it works (and they are real quick in making the cables, and then sending all back to you. Very professional and knowledgeable, all things audio...).
Cheers,
Marianna