I want to use my FNAs from my Bonvoy Amex but we're a family of 2 adults + 2 kids trying to go to Europe (Paris & London in particular). The limited hotels that might within the FNA point limits allowing 4 people in a room ask for points + cash to book that room. The same hotel would allow a FNA to be used if I was only booking for 1 person. Any tips to make the FNA work out in either city?