Here's how I got the numbers I did:

According to a 1980 Seattle Landmark Board record on seattle.gov [^1], the towers on the southwest side of the building are 165ft (50.2m). The document also states that the concrete stepson the SW side are 20ft tall. By OSM `height=` rules, those 20ft are included in the height of the tower (165ft from street level, and the SW side is the lowest side of the building [^2]), but I assume the numbers in the document already include those 20ft. Therefore, we can tag the towers as `building:part=tower` and `height=50.2`.

Now the tricky part. The main building (i.e., everything but the towers on the SW side) is *mostly* flat [^3]. However, I can't find any official (or even unofficial) numbers about the height of that main building section. Referencing an official image of the southwest side of the building [^4], however, we can see that the distance between the top of the concrete stairs and the base of the main roof is approximately one-third the distance between top of said stairs and the top of the towers. Because we know the distance from the stairs to the tower-top to be 165-20=145ft (see previous paragraph), we conclude that the base of the main roof is around 48+20=68ft above street level. We add an additional 5 or so feet for the (low-angle) main roof, and get 73ft (22m) height for the main building.

That means we can tag the main building outline with `height=22`, and then to acknowledge the fuzzy estimation we did, we can also add `height:accuracy=estimate` and `height:source=image;extrapolation`.

Thank you for reading. Feedback is always welcome and would be much appreciated here.

[^1]: https://www.seattle.gov/Documents/Departments/Neighborhoods/HistoricPreservation/Landmarks/RelatedDocuments/st-james-cathedral-designation-nomination.pdf
[^2]: Local knowledge
[^3]: Key word here is mostly. Notably, the corners on the northwest side of the building are significantly shorter, as the bulk of the cathedral is cruciform, but that can be updated later.
[^4]: https://www.stjames-cathedral.org/Tour/images/stjames-penney.gif
