Passat B5.5 Porsche brakes

[Pitzury]

I drive a 2004 Passat 4Motion and I am trying to use the Porsche 36/44mm narrow pad front and 30/34mm rear calipers but I am afraid I will end up with too much rear bias with this setup.
Stock setup on my car was 288mm rotor with one sliding 57mm caliper in the front and 245mm rotor with 38mm single in the rear. Master cylinder is 1” and the car weighs 930kg in the front and 700kg in the rear with one 85kg driver.
I installed the fronts for now using 321mm rotors and I am locking up the fronts and the ABS does not seem to keep up with them. I will in the end probably have to disable the ABS anyway.
For the rear I have the option to use 256,262 or 280mm VAG rotors and the bolt on option would be the 280mm one. There is a 310mm option too but I think that would be too much.
Using this spreadsheet http://sports.racer.net/docs/brakes.xls it looks like from a stock 72/28 now I have 75/25 with the fronts only and will end up with 64/36 if I go with the 280mm and 30/34mm pistons in the rear. It seems that using the 28/30mm rear calipers would be a better choice.
I want to renew the seals and dust boots on the rear calipers too so I don't want to throw more money away testing with the 30/34mm if I will end up using 28/30mm calipers.
Anyone else tried this setup or something similar?