The written request thing is OK, but as your friend mentioned, if presented in the wrong way could come off like a list of chores.
You might consider trying to build a little email communication (or even just a little discussion in the bar or as part of the negotiations in the room) with your intended courtesan prior to your arrival, and send the list in advance. This way you aren’t just springing a list of demands on her, and it gives her a chance to add her own input. Trust me, if you allow your lady to get involved, and incorporate her own ideas, and enjoy herself too, you will be a VERY happy guy!
If it’s more of a fetish situation and you NEED for specific things to happen, then sate that clearly, but still approach it more like a collaboration, and less like demands (even if the request for her to do everything that you demand LOL…in that case: request first, demand during)