Thank you, this is a simple solution which looks good, and I appreciate the time you're putting into this.
My only concern is that because the chapter number is so big, it now extends quite a ways into the page margin. This isn't such a big deal on recto (odd-numbered) pages since there is extra space from the gutter, but it could be an issue on verso (even-numbered) pages. We're using a one-column layout, but I guess this would also be an issue for the second column of a two-column layout.
The ideal solution would be for the two lines affected by the chapter number to shift somewhat to the right, but keep the relative size of indents. The chapter number would outdent relative to its two lines of text, but remain within the overall page margin.