[Boatanchors] Slightly OT: What is the optimum "twist ratio" in window-line

[Phil]

I'm asking this here as I don't belong to any antenna lists right now.

If you were using 450 Ohm window-line to feed a dipole, and you wanted 
to minimize stray radiation or extraneous pickup from the line, about 
how many twists (say per 10 feet of line, or whatever) would you put in it?

Thank you.

-- 
73 de Phil,  KO6BB
http://ko6bb1.multiply.com/ (OTR Blog)
http://www.qsl.net/ko6bb/  (Web Page)

RADIOS:
Grundigs: Satellit 750 (2011), S-350 (2006)&  G6 (2011).
Radio Shack: DX-380 digital portable (circa 1990).
Yaesu: Two FT-8800 Mobiles, VX8R Quad-Band (circa 2010).
Zenith: Royal-7000 Transoceanic (circa 1969).

ACCESSORIES: MFJ 1040C Pre-Selector, W9GR Audio DSP.
ANTENNA: PAR 60 Foot End-Fed, up about 28 feet at Apex.

Central California