Yeah, that Help Center article from 2012 was before the Morph tool was introduced, so I'm with Richard on the extruded Morph solution.
In particular, this kind of arch would often be framed by standard carpenters/framing to the edge of the splay, and then custom hand framing for the splayed reveal/arch - and modeling that part as a Morph captures that it is an extra construction step. If you want to justify the amount of work.
🙂
Rob - Your result looks great. You can make the diagonal line inside the Morph splay in your screenshot invisible, should you be generating views/drawings similar to the screenshot.
One of the forum moderators
AC 28 USA and earlier • macOS Sequoia 15.2, MacBook Pro M2 Max 12CPU/30GPU cores, 32GB