Topband: Antenna advice needed

[Philip M. Roberts]

I have a 72 feet tall tower with a Mosley Pro 57 two feet above it 
and a 6 element 6m beam 18 feet above that.

My question is this what antenna should I use a sloper or an inverted 
L for 160m ? Should I try something else?

I have a 50 feet vertical , it is a Killer on 75m but not so hot on 
160m. I could only make contacts out to 2500 miles. I heard some good 
DX on 160  AO5, 5X, ES,and OK

Phil  W8UV