As noted above the 24 hour visa policy still requires some paperwork I believe when you land and it is not as easy as it used to be. My tour guide has said people with shorter layovers are getting rejected. He emailed me this morning to say he just met a customer/American couple who had a 10.5 hour layover and they were able to make it through. For now, I think I'll stick with doing the tour and forego worrying about the transit hotel. With 18 hour layover I could have done both - here I'll take the tour and find time to sleep on the plane.