When I'm overseas the holds are always 7 days, so I have to plan accordingly (even if staying at a single property, but especially if staying at more than one). Domestic holds are less, but I personally use 4 days as a rule of thumb for domestic.

Like the OP at times I've had to worry about a lengthy trip w/ multiple hotels & holds & worrying that they'd clear before actual expenses+holds ate up the available credit even if the actual charges were going to be less by the time all was said & done.

If I were the OP I'd contact the propert(ies) directly & ask what the daily hold is so s/he can plan accordingly. Also, if s/he knows from experience that the Ritz charges start hitting his cc during the stay he may want to use (for his other hotel stays) a separate card for check-in/holds & then use his main card at check out for both the Ritz & other property stays.

I've stayed at some Marriott properties where the daily hold is 75E & some JW where the daily hold is 100E, so I normally use those as a guideline. My guess is the Ritz might be more, but again it's best to ask in advance.

Cheers.