I have a game that I was hoping to get playtested via soliciting for on the Forge.  Having never done this, I was curious as to how much of a game gets passed on to the play groups.  Do you give them just the bare bones of the system to just to see if it works or a whole manuscript so they can get a feel for the full game?  Or is it different at various stages of testing?

When I've been getting my own stuff playtested, I tend to give as much as I have to any given play group and see if they can play the game as written. Making the game text understandable and useable is just as important as having systemic elements that work in play. So, my advice is to give them what you've got and see if it makes sense and functions for them.

Managing expectation is also good. Let people know what you'll be sending them, how long the document is, what is expected from them, and so on and so forth.

Cheers
Malcolm