Topband: Tophat? Does it have to be at the top?

[Bill]

I would like to operate 160m using a shortened vertical.  I have read
alot about "Tophats" and
I know what they do and why but, have never had an opportunity to put
what I learned about them
into practice.  Now I would like to.
 
My question is:  Does a tophat always have to be at the top?  Or could
it be a "Collar", half way
up the vertical and maybe called a "Scarf"?
 
K2WH