The booking thread, which is the whole mechanism
Everything is arranged in one written thread: the address, the hour, the length and a name, with nothing said aloud and nothing asked about your reasons.
There is no call to make and nothing to dial. The thread is not a way of avoiding a conversation, it is the conversation, and for a guest who would rather compose a message than manage a tone it is the reason this practice is workable at all.
What it has to carry
Four things. The address, with a floor and a room or apartment number. The hour, in Amsterdam time. The length. And either a name from the roster or a sentence about the evening you have in mind. That is a complete booking. Anything beyond it is optional, and the shortest workable message is closer to forty words than to two hundred.
What it will not do
It will not ask what you do, why you are in the city, whether you have done this before or how your week has gone. It will not fill a silence. It will not put a name forward if the one you asked for is busy; the reply says which of the roster is free that evening and the choosing stays entirely with you. A question that comes back is a single question and can be answered with a word.
Keeping it short
Send the whole booking in one message rather than opening with a greeting and waiting. Give the address before it is asked for. Say the length rather than asking what is recommended, and if you genuinely do not know, name the two you are choosing between. Guests who want the thread to end quickly should also put the quiet request in that same first message, since it belongs with the booking rather than after it. The full walkthrough is on the booking page.