Increasing Hydration and Loaf Size

Hi All!

Today I will be baking a 3rd loaf using this recipe:
http://www.thefreshloaf.com/node/64738/55-hydration-sourdough-4753-hard-red-wwheb-bread-flour

780g loaf (Including Salt, do bakers normally include the salt when discussing the weight of a loaf???)
50:50 Hard Read:Bread Flour

The first loaf was 55% hydration. Came out beautifully.
The second loaf was 75% hydration (Baked it last night, eating it now). Came out just as beautiful.

I will be baking the 3rd loaf today with 85% hydration.

Question: When increasing the hydration of the loaf, if my goal is to keep the loaf the same size (not weight), in order to make sure it doesn't spill out of my romertopf, should I reduce the flour?

And, if so, by how much? Should I strive to keep the overall weight of loaf the same? The reason I ask is because, I know that most of the water bakes off, so I assume most of the loaves volume comes from the flour amount and how much the bread rose.

My gut feeling is that I should keep the flour amounts mostly the same, maybe reduce it a little, but not reduce it even close to enough to get back to the original recipe weight.