I'm just gonna throw this out here!
But, if you have the original roof.. metal, then shingles and a shake roof on top of that, you've got much more weight on top than your home can handle!
How were the trusses constructed, and out of what?
If you've got 2x3 frame walls... it can't take that amount of weight from the roof... and roof over.
Bracing anything won't do it, you need to really look at the structure of your home.
If you use the sheet rock right now, you'll be doing even more repairs down the road.
Our homes aren't designed to like stick builts. If you got 2x3 exterior framing, then you really have to be careful.
Like I said, just my opinion!