whole wheat 1-2-3 sourdough

Made the old standby again.  I really love this bread.  I have a question though.  First, the recipe:

9 oz starter (100% hydration)

9 oz whole wheat flour

9 oz white flour

9 oz bread flour

18 oz water

1 T salt

I mixed it all in my KA for about 5 minutes, then did 2 stretch and folds over an hour.  The dough was VERY wet so I folded in about 1/8 cup flour.  It retarded overnight in the fridge, then one more stretch and fold, divide, preshape.  Rest and rise for about an hour.  Then shaped and pulled taut.

Cooked with steam in a 450 °F oven for 35-40 minutes.  It had good oven spring, and looks GREAT.

Here is my question:

my bread is pretty flat before I put it in the oven.  It doesn't hold its shape while rising.  Maybe I shouldn't worry about it, but would slightly drier dough help here?  my dough is very wet, but it usually tastes great.  Any thoughts?  I supposed I could rise it upside down in a towel-lined-flour-covered bowl or wicker basket.  But I don't have 2...