Help downgrading to install CM12 topic

Hi!
I'm quite new to this model, but very familiarized with IT and nexus devices, as well as some samsung ones.
I got the phone one week ago and after updating to the latest 5.0 stock firmware, I think in some days I'll be good to go to AOSP and never look back :)
Now, I have been doing my homework and reading around how to do it, but I finally must ask some questions that I still cannot figure out.
Model: European D855 16Gb
Current ROM: V20f-EUR-XX
Baseband: MPSS.DI.2.0.1.c1.13-00048-M8974AAAANPZM-1

First of all: I read somewhere around xda that I'd better use .tot files instead of KDZ because some people report bricks with the KDZ files (Hardbrick or softbrick, anyway?)
Second: I am following this manual: http://www.androidrootz.com/2014/07/...-variants.html But it's from july 2014, so perhaps there are some caveats with the latest 5.0 version?

Those are my two questions, and I think they are pretty critical, since I'm risking a hard brick if I don't do them right.
About how to stump and bump once back in KitKat, I have no problem, it's pretty straightforward, so I don't need advice on that.

Any help will be welcome.

Thanks!