Vader in the Banite sith line

After he killed Sheev, its never told if he got the power amp that one gets from killing their master. Did he get it? If not, was because he was a light sider? Or because Sheev's spirit was still around? Could it be that he just rejected the power?

Darth Vader turned to the light side of the force. He was redeemed from the darkside of the force.

I don't think the exact mechanics of the Banite power amp have ever been explained, have they? We have a couple examples of a Sith Apprentice seemingly feeling a growth in their power the moment they kill their Master, but we don't really know why it happens, do we? It honestly poses a lot of questions.

1. Is the apprentice the only one who can get that amp by killing the master? If so, that would imply it's some technique the master trained the apprentice in. But given the context of the amps we've seen, I find this extremely hard to believe.

2. If it's not a learned technique that leads to the amp, would anyone who kills the master get the amp? What if the Sith master is struck down in a duel with a Jedi? Surely the Jedi wouldn't get a Banite amp. I find it unlikely a light sider could gain this power up. 

3. If it's not a learned technique, and not just anyone gets the buff, does the killer have to be a dark side user? Would that mean if Talzin had killed Sidious, Talzin would suddenly gain the Banite amp?

I honestly hate that the Banite amp was ever introduced. The Rule of Two makes enough sense as is, with a master training a single apprentice until the apprentice is powerful enough to kill the master. This ensures the line will always grow with each consecutive apprentice to successfully defeat their master. There's no need for the writers to have added in an additional power boost with each master's death. It just feels weird and unnecessary to me, and overcomplicates things.

Sidious didn't die, so I presume not.

Sidious was resurrected. In order to be resurrected you would have to die first.

I obviously meant a spirit death.

Well I don't think spirit death matters in this case, considering Bane was a spirit long after physical death, and the Banite line kept growing stronger anyways.