Topband: More on two wire Bevs

[Cqtestk4xs at aol.com]

Planning on putting up 880 footers.  One for NE/SW and the  other NW/ SE.  
I'm not planning on using relays etc for these, just  planning on running 
two wires parallel to each other for the 880 feet with the  usual xfrmr on one 
end and a terminating resistor on the end for each parallel  Beverage.   
They will be approximately 10 feet above the  ground. What is the minimum 
spacing required  between the parallel  wires for good performance?  Can they be 
spaced above each other ...perhaps  a foot apart?  Ideas?
 
73 Bill K4XS/KH7XS