I know that this is an old post, but I thought I'd add a little anyway.
I am relative newbie and have started playing with higher hydration breads - 80%. I use the stretch and fold technique to help develop the gluten (
http://www.fornobravo.com/pizzaquest/instructionals/59-written-recipes/175-the-stretch-and-fold-method.html) . I use the direction of my stretch and folds to pre-shape my loaf - a little like getting the gluten going in the right direction for the shape of your final loaf. If you do three or four rounds of stretch and fold you will feel the gluten getting noticeably tighter. I use the final round of stretching and folding as my final shaping before final proofing.
I have noticed that the longer to do it's final proof, the greater the chance of the dough 'flowing'. This will happen if the dough over proofs and stretches the gluten to 'breaking point'. But I also I think this is partly because the gluten gets to relax too much for the final proof if it is left too long.
Also, the longer I leave the bread to proof overall, the weaker the gluten structure is, possibly because the enzymes and acids from the sourdough starter start breaking down the gluten then the gluten strength is weakened. I think that if I use less starter then this effect is minimised for longer fermentations.
I hope that this makes sense and is useful.
Mat
What some call health, if purchased by perpetual anxiety about diet, isn't much better than tedious disease.