OK. Here are some results. First, the Verhoeven article says that the alpha angle on a razor is 11-12 degrees and the bevel is 15-19 degrees.

I measured 5 razors, all 5/8 and new or very lightly honed. The Bergischer Lowe has a 7/32 spine width. The width to spine ratio is 2.86:1 and the bevel angle 19.8. I measured another Dovo, Fritz Bracht for comparison and it was 3/16. I also measured a TI and a Stehlo, which were the same. That's a ratio of 3.33:1 and an angle of 17 degrees. Then a Droescher was 5/32, which is a ratio of 4:1 and an angle of 14.2 degrees. It's not the thinnest spine I've seen, but I didn't have time to search one out.

So, just grabbing a few razors I have a ratio range of 2.85 through 4 and an angle range of 14 to nearly 20 degrees. Also we know why the BL has such a wide spine. They did it to show off the worked back.

Seriously, I doubt whether bevel angle is a very precise thing. And I'm not surprized. There's a lot of leeway with knives, depending on the user's needs. Why should it be any different for razors? Verhoeven says 15-19 degrees and I found 14-20 without really trying.

It makes sense that it wouldn't be precise. The manufacturers knew the level of skill of their users. We've seen some of their handiwork. To maximize reliability they would want a large angle range that would work, not a narrow one. After all, they wouldn't want the razor to lose effectiveness because of the expected imprecise honing.