but ...

there are plenty of other instances where the post must be drilled right through. To fit the girts to the outside face is toute apparent but why the need to fix (nail) to the braces when they (usually) cover but a small corner of a wall siding?

The marking up, I can see would be easier; I'm planning to fit my house braces central to the girts, then I can hang misteltoe & holly over them at Xmas!