Caliper upgrade adapter questions

[very~worn~944]

Hey guys, I have a tricky question for guys with experience in this area. I have a set of Cayman S calipers. I am looking to use them on my 86 turbo (with 87 front suspension) using 928 GTS rotors (correct offset when using Big Red conversion kits). The piston size is 36mm/40mm, same as factory 944 turbo calipers which makes me think the hydraulics will work relatively simply. The rotor diameter of a Cayman S is 319mm, opposed to the 322mm of a 928 GTS rotor. The thickness is 28mm, opposed to the 32mm GTS rotor.

Here in lies my problem...For the thicker rotor I would need to shave about 1mm off the pad pins in the caliper (n/p). The pad height is the same for a cayman S caliper as a 993 Big Red, but since the GTS rotor is 3mm larger in diameter I think I need to space the Cayman calipers 3mm higher off the spindle than a Big Red caliper. *see edit

The issue is the offset of the Caliper. A Big Red caliper is 55mm from the centerline of the rotor to the center of the mounting bolts. A Cayman S caliper is ~52mm. The Rotor centerline would need to be 3mm inward on the car (eliminating the use of the GTS rotors). Instead I am looking at mounting the Cayman S caliper 3mm farther out on the vehicle than a Big Red Caliper. Then I could use GTS rotors.

Looking at the adapter blocks available for Big Red conversions, I don't think there is enough structural material in the adapter to drill the bolt bore 3mm farther out. Would it be possible to machine new adapters 3mm taller...AND make them "wrap" around the spindle mounting point to provide more metal to work with? Check out my SWEET paint diagram, and this picture of a BIG RED adapter, and let me know what you think!!

*EDIT: The pads sit 3.2mm LOWER in the Cayman S caliper measured to the mounting plane in comparison to the Big Red Caliper...so to make the pads contact the GTS rotor in the same place as they would with Big Reds, the Cayman S caliper will need to be mounted 3.2mm higher than the Big Red- not the 3mm I stated earlier