If your having problems with a shoulder width stance, then its definately something you should try. I made the switch last year, and its made a huge difference. For me its much stronger. Im raw btw.
Now i dont know what the definitions of wide are, but im guessing my heels are about 8 or 9 inches outside my shoulders.
The squat itself is the best stretch, provided form is sound, and weight is lightish.
Knees out and toes out is going to help with depth. As said above a few times!
As mom-in-MD said (i think?) with BW only, squat down into the bottom position or as close as you can get. Hold that position for a few seconds until it gets uncomfortable, then repeat (maybe 4 or 5 times) Holding onto the rack/uprights can help. I did these as often as i could.
Provided your fairly flexible, and were hitting good depth before, it shouldnt take too long, it didnt with me anyway.
Then again i might be not be as wide as you were thinking.