Hi Rudl,
Well, here's a short video of me making those frames match:



In the first "chink" part, I just get the edges of the top and bottom piece and loft and planar a little solid to fill the gap.

For the second one, you can see me cut a new angle on the piece so I can get a matching seam where they meet. But my cut was just arbitrary to make a meeting.

Maybe wait a bit because I think there are some pro architechs here that may know better how a situation like this should be handled. I think there is something wrong with the setup, but it may just be because you have various angles meeting in more than a couple planes which make the miter more than just "2 45's meeting". Like someone could tell you that if the one is at 60 and the other is at -10 then you need this math to get the vector for the miter..... etc....

Anyway