I don't know if you will get sufficient depth of tan w/ one of the commercial, non-bb tanning products in one day. I used ProTan for both of my shows, however I did 3 layers of it, starting 3 days prior (spray on, let dry, sleep in long sleeves & pants, wake up, take a shower, repeat that night and the following night).
One guy did some base tan development via tanning bed, but put on Dream Tan the morning of the show -- he looked like a shiny orange guy in the morning show, but took a shower between AM & PM show and looked great for the PM show. This leads me to believe that leaving Dream Tan on for something like 4-5 hours and then showering it off will leave a nice tan in 1 day. I would have to test it once for myself.
The thing w/ Dream Tan when you first put it on is that you can't smear it after its on because it will smudge & possibly smear off on your posing suit. Try the thing about leaving it on for a couple hours & then showering it off - it may soak in enough in those hours to survive a shower and not be smeary.