[Q] Japanese Samsung Galaxy S3 SC-06D

Hello folks, so I have an NTT Docomo Samsung Galaxy S3 SC-06D which I want to root.

I only really want to root it to remove the bloat and so I can use tethering.

I'm on Ubuntu, and have Heimdall installed.

I rooted my Pipo M9 using ADB, that was simple enough.

I've spent hours reading through this site and I just want some final confirmation before I start.

I still don't really know which ROM to flash, and how.

Do I use ADB or Heimdall?

Android Version 4.1.2

Kernel Version 3.0.31-1247701-user

Build number JZ054K.SC06dOMBMF1

I'm expecting the usual replies of "use the search engine", et al. But, can somebody point me in the right direction? Especially somebody who has rooted the same phone.

Thanks a lot.