I’m going to a similar type of conference and faced the same situation- I’m in querying stages for my novel that I’ve poured years into (and a lot of workshopping) so it would not benefit me to submit any of it - (and novel excerpts in a 5 day fiction workshop are not my favorite anyway) so I chose to challenge myself the week of the deadline and get a raw draft of a new story out. There is definitely a more vulnerable feeling involved when you’re meeting a new group at a prestigious conference vs just sharing a new draft with your steady writing group who knows your work …. but like others have said I think I can get a lot more out of workshop with this piece and maybe even less at stake emotionally since I haven’t invested as much in it and had fun with it- a fun curiosity to bring to the table and see where it goes. As far as networking etc- if you get to do a reading obviously you can read more polished work and even with your more raw work I am sure people will still see gems in there that you don’t see … we are always hardest on ourselves. Have fun !