Even bolder, you could use the same prompt for multiple stories in their own thread. Or, if you like epics, have multiple arcs in the same story, and have each arc deal with the prompt in some arc specific way. It's really up to you, just as long as you write and enjoy it. You can also post as many scenes as you like each week, as long as one of them deals with the prompt.
If you're willing to alternate on the prompts, that would help. My stories are a lot better when someone tosses out a suggestion I hadn't even thought of. Which leads to the "all at once or bit by bit" question. I would share the secret of writing great fiction but I have no clue what it is. I will tell you one of my stories, though.
If you read the "Ought Five and One Two Three" thread (Sci-Fi -> Fireside -> Futuristic and Space Opera), that's me writing and presenting on a mostly daily basis. While it is an incredibly rough draft it let others read and critique real time in the "[TDW Peanut Gallery] Comments and Critique" thread. The comments made it a much better story than I had planned.
How about this? I'll post the first prompt here shortly. It will be in a new thread. If you choose to participate, start your stor(y/ies) and give links to them in the Challenge thread. If you want to do a "wait ten and reveal" then start your thread and put stuff in when you choose.
Next weekend Minstrelgirl451 posts the challenge. Just let us anticipation challenged people know about when to expect it.

That work for you?