Topband: 160m Top loaded vertical

[ct1ilt at sapo.pt]

Hi Topbanders,

I am about to replace my wire vertical to a 28 meter (91,8 feet) High alluminium vertical with top loading hats.

My questions are: 

  * Should I use 2 top loading wires or 4 ? (how do I calculate the length of the 4 wires or the 2 wires?)
  * Is there any difference if I put the top loading wires at 25m high instead of beeing right at the top (at 28m) ?

Thanks for help.

Filipe Lopes CT1ILT aka CR6K