Palal, thanks for the detailed pointer to FreshenUp.
After some more research, I decided to go with a day-rate for the Hyatt (USD 74,50 from 10am to 6pm). The Hilton is either USD 129 or USD 59 for a day-rate from 10am-5pm, depending on who you talk to
Booking a normal night-rate from the day before, would require a pre-checkin by phone, check-out would be noon, late-checkout (not guaranteed), 2pm or 3pm. I did not want to risk being late at the hotel due to the flight being delayed and having to leave again a few hours later...
We will have breakfast at the Hyatt (buffet USD 19,50) and just enjoy the day with loads of sleep
/ xanth