[400TT]

Sounds like you are going to have to be patient for that VIN. QLD is no different, it's months for QT to approve.

Stephen, you will have to modify/disable the internal proportioning valve in that master cylinder of yours, then fit an in-line manual adjustable proportioning unit. Speak to a brake master cylinder reconditioning place, they will know what to do and what's the best approach with your master cylinder. They might also be able to correct the brake balance by swapping you to a different master cylinder.

Or alternatively you can fit better front calipers that have smaller piston capacity, that will also fix your brake balance and improve front braking. Nissan Skyline calipers should perfect piston size for you, but you will need to make sure you can mount/adapt them. The location of the mounting tangs on the calipers could make them anywhere from easy to difficult to mount.

Your pedal ratio is right, so you should be able to get great feeling brakes.