I don't think you'll get the R31 front discs to fit. Prove me wrong, and document it
We all benefit that way.

There's 3 problems.
1. Rotor offset when fitted with the best possible hub.
2. Getting a hub to suit the 1200 axle.
3. Getting a caliper to suit the axles mounting points. Modification to the caliper mounting points almost always voids road worthiness.

The 1200 strut uses small bearings, and these hubs to suit aren't too common in other Nissans.

I'm not running modified 180B ones for fun!. It's so that the commodore caliper slip onto the original bolt holes on the 180B Axle.
Then I use the Verada discs and machine the 180B hub to suit the disc. And redrill the disc holes to suit the 180B hub.

Chris