C41 and CPE2

Hi all

I'm about to dive back (after 25 years) into C41. I'll be using 5x4 and 120, and a CPE2 with 2553 tank, 5x4 holders and 120 spirals. I'm also going to try the Rollei Digibase chems, and film will be Portra's.
I'm used to B+W film/chemistry in the Jobo, and 5x4 works well (4 sheets per spiral) but using the 120 reels, with certain films there can be a ruinous density build up down both long sides of the film. I assume this is localised over agitation where the film meets the spiral - anyone else noticed this?
Does colour film/chems work in the same way? Is it as responsive to agitation like B+W film is, or is it purely the time it spends in the dev that determines density.
I know I'll have to run a few tests, but while I'm waiting for the chems to arive it would be good to hear from other C41/CPE2/120 users, and how you rate the negs.

Cheers
Richard

Richard, what films are you talking about? "with certain films there can be a ruinous density build up "

Using Kodak or Ilford, I never notice any problems.

I've noticed this edge build up with FP4, but the worst case is Foma 100. I think this film is really agitation sensitive.

Sometimes it's possible to see, in this density area, shapes that match the many notches round the spirals.

Also it seems like a classic cpe2/film dev issue - some people reckon they get flawless negs, and others are plagued by un-even dev issues. I went back to inversion deving with 120 because of this.

Richard

Are these problems with the 1501 plastic reels or the 1502 stainless steel reels?