Hi Pawel,
I've been away from this thread for a while and it seems i've missed a lot!
No offence, but it seems like you lost your way a bit with this build. I think that in your strive for authenticity, the comments here have conflicted a little with your artistic vision and the model has suffered slightly.
Now don't be disheartened, its a great build and I don't want to knock anyone for commenting, every post has been intelligent and well thought through.
I'm by no means and expert when it comes to zimmerit, but I beleive that is is not always portrayed correctly and there is a lack of information for us modellers on the subject.
Pawel my freind, I know exactly the look you wanted to create and that Tiger B on planet armour you linked to is a lovely build, and I can see where you are drawing your inspiration. May I also direct you to this build which perhaps has the exact look you were going for:
BergepantherflakHowever, I'm not a fan of the look of the zimmerit on this model, despite thinking the rest of the build is a work of art.
My main reason is just that far too much zimmerit is missing (and I think the primer is too pink). On some of your panels perhaps 40% is missing, and I think perhaps this is the reason that you are encountering problems with the bare areas, and what colour they should be.
Over such big spaces you need to show the kind of zimmerit layering colours described in the posts here to be historically accurate.
As has been mentioned, the type of damage needed to show this lack of zimmerit, the tank would have to have been peppered with 20mm or something to lose so much and in such large chunks.
I know its perhaps too late, but more zimmerit and less primer could solve your problems.
When I build my Stug IV if you remember, I approached the zimmerit chipping with the following philosophy:
I applied putty to make the zimmerit, and tried to apply it everywhere it should go. However, thats obviously not always possible, and some areas will get missed, the zimmerit will not be thick enouigh, flake off or be damaged in some way during construction. When painting I then painted any of the above areas in the raw zimmerit colour (beleived by me to be a light sand at the time, though perhaps it should have been grey?) and anywhere the plastic showed through (ie. no putty at all) got painted primer red, the largest area (rear fender) also got battle damage to explain the absence of the zimmerit.
Now I know that I wasn't going for the same look and that it's a bit late to be saying all this now, but I think they ket thing you are missing is the parts that are not perfect zimmerit and not bare metal, which should be quite a large proportion of a damaged area. Something probably best done during the application process, though I see you have attempted to remedy this during recent posts. Your last post is almost there in my opinion, I'd fill those grey areas now with peices of undamaged zimmerit and some bits of primer red that would then give the impression of 'depth' to the zimmerit.
I hope this all makes sense and you don't take offence, you are a talented modeller and this will be a great build once you've overcome this issue.
Likewise I don't want to offend anyone who has posted, these are just my own views.
Keep up the work mate, what you are doing is striving for perfection and you will reach it!
James