Duchen -
I'm not sure how to answer your question.
You might be better served in the C-band section of the forum if you are complicating the question with a 4DTV.
One rule to consider is this.
Someone (some receiver) has to control the V/H selection at the LNB.
Any other receivers should probably have their "LNB Power" turned off.
That holds true regardless which way you connect the receivers.
As to the question of splitters, I don't much care for the whole concept.
And when you use them, don't you also generally want a "DC block(er)" to the receivers that don't power the LNB?
I think that's a safety feature, if someone accidentally screws up the receiver settings.
...or it might be an old concept from when receivers may not have been able to turn off their LNB power.
I'm just giving you more questions, not answers, but at least you'll know what you don't know.
...and as for the other matter, if you see a male under 30, sitting in a hot car, do you make any assumptions about his driving habits?
What if the same guy is parked in an old station wagon, or a stock '72 beetle?
Yea, some old guys have the hot cars, and maybe they drive better (or not).