No pictures but I can tell you how I make my disc mounts. I use coroplast for this since I have lots of pieces of it laying around. First thing is cut a piece of coro and drill or otherwise make the 2 holes so when you have made the right shape to fit around the disc assembly you can then bolt the coro bracket to the disc kit. Basically the coro makes a great template, it is easy to cut and shape and is rigid enough to be able to bolt the disc assy to if you are careful not to over tighten the 2 bolts.
Once you are happy with the shape, remove the coro, use it to trace onto a piece of metal. When the metal has been shaped bolt it to the disc kit and use a piece of wire to tighten the caliper onto the disc rotor after which you can tack weld the bracket to your frame. I have also in the past placed a cold wet piece of kleenix over the caliper assembly to prevent any heat damage to the caliper. Once tacked in place, remove the piece of wire and give the wheel a spin to ensure that all clearances are good. If so then remove the caliper and weld up your bracket. Small washers can be used if needed to make minor adjustments.
One would think that there's some capability for fine adjustments in disc brakes. I've never actually touched one; hearing there might not be is disappointing. Must concede that once it's set up right, though, it should stay there. Still, puts the onus on the frame builder to position it exactly right.
Every caliper I've ever seen had some wiggle room in the mounting area. Once the mount is made, bolt it to the caliper and set any wiggle room to the middle then offer up to the disc and clamp in place via the caliper itself prior to welding. If welding warps anything then the wiggle room will allow compensation.
There is room for adjustment built in to the calipers. Usually the piece the caliper bolts to, I'll call it the bridge has elongated holes that allow the caliper to move closer to or further from the disc. That gives a bit of room for misalignment.