I had this very same question at the Marriott in Dublin, OH. I'm currently Platinum with Marriott, so that's probably going to put you towards the front of the line. Marriott told me to call the hotel directly after reserving online, and they will add a request for the lounge floor in the notes of the reservation. Personally, I've found that most of the rooms on the top floor are suites. I've also found that there tends to be more double-bed rooms on that floor vs. king size beds. So, I went into my Marriott profile and switched my bed pref. to be double beds in hopes that it would put me in a better spot for the top floor (every time I would check-in and ask for the top floor, I would always get "we only have rooms with two beds, no king"). As for points, I personally don't think it matters, as I have very few points and made Platinum off of the Marriott Platinum Status Challenge.