I think Brad has a grasp of it now....
And mo you may have some points about the brace also.
But if the post bows in and you layout correctly you should have a deep housing.
If the braces is too long, it will show up when you do a fit up test with all the pieces of that bent. At that time you could trim the long brace back to correct it and make it work.
If the post bows out and the brace is too short then you'll have to cut another longer brace, possibly mapping as you have mentioned.
I would think it would be easier to trim a little off something that's too long then to have to replace the entire piece because it's too short....
Jim Rogers