38mm offset for our triples,
btw, what did you do for steering stop bolts that screw into the triples? I have some big head allen bolts in there with some nuts screwed on to space the bolt up far enough to hit the steering stop... looks like it could do with being turned down a little to get the most out of the turning circle.
I like your rear brake mod. Visually I am not too sure of the adjustable cable ferules, but they seem to do the job very well.
I was trying to think of a downside to doing a cable instead of a rod-
I suppose if you get a large rock fly up and hit it it might more easily apply the rear brake locking up the rear wheel... briefly... but being a cable it will just bounce back out rather than bend in, and it would have to be at a very awkward moment for the rear wheel braking to actually do too much damage.