If the full manuscripts are not posted in SYW but only in excerpts for the purpose of constructive criticism, then I doubt there would be any copyright issues.
Why not make separate discussion thread for each story in SYW instead?
Eg., if I want to discuss a story, I make a thread with the following subject line format:
AW Western Contest Discussion: Entry [INSERT NUMBER], Title [INSERT TITLE].
And then everyone who wants to say something about the story can post in the thread. The story itself can be linked to from the OP of the thread.
No?
PS. Those who sent their crits to you in PMs can locate them in the Sent items and post them into the threads.
PPS. I'm procrastinating again, it seems like.