I'd suggest you see the prossie for a 1hr booking before deciding to have an overnight.
That has got to be Rule No.1 if you really have to have an Overnight.
Before I started on this Board, I used to be a fan of them; but always with someone I'd spent at least an hour in the day time at least once before.
Then more experienced punters on here than me pointed out a couple of simple facts: 1] you are paying the girl to sleep for some of the time which makes an Overnight booking poorer VFM than a longer [3 - 4 hrs] daytime booking; 2] you need to choose your day carefully, particularly if you have to go to work the next morning!!
One of my Regulars and I now enjoy a 4-hour session from time to time. It starts about 11.30 a.m., with a break [which she doesn't include in my 4 hours] for a cuppa and a sarnie, just short of halfway through.