Hi Gyra,
You've pretty much got it right - but it's the CALIPER mounting holes in the factory bracket that (I believe) need to be welded up & redrilled lower down.
Ash (zr240) can confirm all of this...
You won't have any bias issue, but you may end up with a soft or longer brake pedal.
A 280ZX (15/16") MC is a good upgrade.
If you go to larger caliper on the FRONT, you may need to upgrade to a 1" MC. (PBR No: JB1419).