The LNB can put out only Vertical or Horizontal signals, depending on whether it receives 12 volts or 18 volts.
That's why the solution above can't work.
Say one receiver wants Vertical and one wants Horizontal.
What will the LNB do? What will all the other receivers get?
The bandstacked LNBS put both Vertical and stacked in frequency above that, Horizontal transponders.
So, they work with a single wire.
Please re-read the post above for all the solutions that I can think of.
PS: you say the dish is elliptical... look directly into the feedhorn...
Is it round? Elliptical? Could you post a picture?
Cause, if the feed is round, then it treats the dish as round.