I have a brand new 300m spool of 50lb Spectra Extreme Braid you can have for $30 delivered if you are keen.
I bought it for a sea reel I no longer have use for and is a bit heavy for the Waitaki Lakes and canals.
Thickness is 0.36mm which puts it comparable to about 18lb mono.
Check this link for the charts:
http://www.mels-place.com/Contents/ABCs … meters.htm
PM me if interested.