Hi Queenie,
I started posting my first story precisely because I was part way through and needed some feedback and some outside pressure to encourage me to finish it. I had gone as far as I could on my own. And guess what--it worked! Besides one-shots, I have never had a story finished before I began posting it. I need the feedback to help me decide where the story should go.
That said, I do feel an obligation to finish a story once I start posting it. I don't think it's fair to leave the readers hanging. That's why I'm pushing myself to finish Man Under, even though it's been quite a while. I won't start posting the last few parts until they are finished so that once they start coming again the readers will know that the end is in sight and they--unlike my poor betas--won't have to wait weeks or months between parts.
I would think about how committed you are to finishing the story and post a warning to that effect. Either "I don't know whether this story will work or not, but if you're up for the risk you can help me decide," or "I'd really like to finish this and could use your help." Then it's reader beware and forewarned is forearmed.
Good luck!
Happy
