Nice shot, Danilo, even despite the field rotation. Love those big old Mamiyas - I shoot the 645 and Press 6x9 myself, but have always been tempted by the 67s as well.
I use a free program called Xnview to view and make quick adjustments to images. It has a particularly good auto-levels function (CTRL + ALT + L) which rarely fails to sort out colour-cast and contrast issues or white-balance corrections. I tried this on your image in Xnview and I think it improved the colours - they're still neutral (which seemed to be your intent in your new process), but the blue-ish colour cast is gone and the background is more neutral.
BTW I really admire your web design and the meticulous record keeping which accompanies each of your photos!
Cheers,
Ray