For a P2 the offset for the Front standard is 25mm (24.5mm exactly) down and right (standing behind the camera). These were the numbers for my Sinarback 23 with the macroscan, and also for my 75H with the Sinar M as shutter. This should center the chip. The rear standard stays on zero.
I used the 54H for a while, attached to the macroscan, and the numbers were the same.
This assumes P2 4x5" standards, for 8x10 inch standards, it might be different.
Markus