All the variables, when looking at whether to open with your weakest hands, are 'known' except how much of the pot you can realize when you get flatted and see a flop.

Anyone have any ideas on how to think about this problem?

For example btn opens a weak hand and bb flats with a 50% - 3b range. We still usually have ~ 40%
How much do we realize?
I assume that it is not less than 40% because we have position and the 'the uncapped' pre-flop range.
My hunch is that the position is VERY important and the uncapped pre-flop range is not important at all.

All thoughts appreciated, Thanks