You trawled thru posts here, there and elsewhere and now what? You don't know a bit as you was nowhere and you did not read carefully because if you will do that, you also will know that there is not .761 rooted as the developers do not bother about a 1,8 MB update from .757 as it means they have to remake a whole ROM of 1GB just for 1,8MB.
The latest Stock Pre-Rooted ROM it's here: http://forum.xda-developers.com/show....php?t=2711982
To get to that Pre-Rooted (full Root) Stock ROM you have to do 3 steps, Downgrade to .534, Install lates Dualrecovery then follow the instructions from the link I posted from the line How To Update to .757
All for Locked Bootloader.
About Recovery, the recovery have 3 type of recoveries implemented, CWM, Philz and TWRP, I recommend TWRP for everything you do and forget CWM even if is there.
Doing Root your warranty will not be voided. There is no other way to get Full Root on your Phone and nobody will change stuff as you like.
Just do like I said and have a nice time with your Z1.
---------- Post added at 12:49 AM ---------- Previous post was at 12:12 AM ----------
I find something what will interest you as you looking for NCB.
This should be Pre-Rooted Files to .761.
Follow the same steps of installation like on NUT thread form the Line How to Update.
IF I HELPED DO NOT SAY THANKS, CLICK IT.
My Evolution: Sony Xperia Z1 - UB + 4.3 Rooted + Deodexed, HTC HD2, HTC Diamond 2, HTC HD Blackstone, Nokia 7070 Prism, Qtek 9100, Nokia 3100, Motorola T720i, Nokia 3310, Sony Ericson PF 768 (Blue)
How Get Root on Sony Xperia Z1 with Locked Bootloader and the Latest Android 4.4