IIRC Tim Zowada made an angle measuring device from Verhoeven's description, and measured the final bevel on Feathers to be 25 degrees.
Armed with this I got with Josh Earl and had him make me a wedge with a 25 degree honing angle (the final razor came out to about 24 degrees, 25 degrees with a couple layers of tape) and it shaves just fine.
My NOS-when-I-got-it Wonderedge has a pretty steep honing angle as well, it's about 18.7 degrees IIRC.