Thanks folks for input.
Decision: I'll stick witht he 503CW/V System.
I just received a mint 40 CFE IF T* and had last weekend to test it out.
WOW, a very nice improvement over the 50 in contrast and saturation with my P-45 back. Plus, the 40mm gives me that little extra width that I've wanted on several occasions and found missing in the 50mm.
In short, very pleased with it, other than it's price!
Hopefully, we'll see more Zeiss updated lenses coming out in the future that match the 40mm CFE IF. They can start with the 100 and 150 and I'll be delighted!
Jack