You may have gone the wrong way with the extra caliper mounting. Due to the hub placement the extra disc sits much further in the the original. That means the caliper needs to sit further in as well, fitting the brace behind the caliper mount actually helps to space it away from the fork slider and even then it requires some additional spacing. The lower caliper bolt (the 8mm one) needs spacing as well, around 5-6mm IIRC. If you don't space it you'll find the brake pads are sitting at an angle to the disc, braking from the disc will be very poor until the pads started to wear to accommodate the angle, they'll chamfer like hell. Best way to test this is to retract the pads inside the caliper, remove the mounting bolts from the fork slider and press the caliper against the disc from the outside, watch where the mounting holes move to, you should see them sitting in the air around 5-6mm away from the fork slider, that's how much you need to space them away.
If you doubt this info look at pics of everyone who's done this mod and you'll find the brace behind the caliper mount to help space it out.
The other way is to space the disc away from the hub BUT that tends to leave no space for the speedo drive to fit, not a big problem if you've come up with an alternative way to running the speedo.
Do like the way you've run the brake lines, might not work so well on a standard bike but on a custom job like this, yeah it works.