What filter system and CP filter for my CONTAX 645?
 

I just acruired a new CONTAX 645 camera gear including 5 lenses. The
diameter size is either 72 mm or 95 mm. Now I am looking for a set of
quality filters (a CP, several ND and color enhance filters) and filter
system for it. Two of my wide-angle lenses have 95 mm diameter size.
Vignetting could be a problem if using CP with a Lee foundation 100 or
Cokin x Pro filter holder. There must be many experienced MF camera
owners can help answer my basic questions:
(1) Lee Foundation 100 or Cokin X Pro, which one is better for my CONTAX
645?
(2) What size rectangular filters I need? As for optical quality, which
one is better Singh-Ray or Lee filters?
(3) A wide-angle B+W CP filter cost more than $360, it worth the money?
(4) There have been a lots of discussion on vignetting issues. Based on
my reading on-line, it seems to be difficult to avoid vignetting when
using super wide-angle lenses even if you use a right filter holder
system. Is this true? What is your solution/advice for this problem?
Thanks in advance.

Ronald