Nagrom, the 54.

Only problem is the bottom bracket drop of the bk is only estimated by a few people at 40mm. Also not sure what size tires they used when measuring stand over. Probably 23cm.

Tried again and this time came up with a 363 fork length.

Used a stand over height of 819 for one side, 15 for the angle. Which came out to 847 - 334 (radius of a 700c rim with 23c tire) - 150 (head tube length) = 363 fork length.

Probably doing it all wrong to be honest.

Scrod, I saw your bare knuckle. What is your cycling inseam if you don't mind? Exposed seat post (on non sloping frames) is also a good comparison. Thanks!!