Thanks!
I discovered that the Kindle does not have options to setup a proxy
Any reason (we can't change) why the BBB rules don't survive a reboot?
This filtering idea is not that safe if it gets reseted accidentally after a reboot.
And of course, just to troll me, my other Kindle PW(2) just got updated to 5.7.2.1 last night...
Good thing I updated its jailbreak last week! KUAL is still working