Sewing is like solving a puzzle...

I can't figure out how to put this frickin waist together, I thought I would be able to just drawstring to fit but now I'm getting this bunching/gaping happening? I feel like this has a straightforward solution, and I've just been looking at it for so long that I'm not seeing it.

Originally the casing around the drawstring extended farther in each side and had less of a gap from where one side comes out to the other, I feel like that's probably the way to go so there's just less loose fabric in between. But the reason I made the gap bigger was that with both strings coming out closer together it was awkward to tie. Maybe somewhere in between, only an inch or two between both openings?

Update:
I think I've solved it by reverting to the original design. Time to wrap this thing up.