[TowerTalk] Heavy Guage Copper Wire Source??

[Michael Tope]

With all this talk about lightning, I was thinking it might be 
prudent to throw in a few heavy guage bare copper conductors 
into the radial system that I am planning to install for my 
short 160 meter vertical:

http://www.dellroy.com/W4EF's-Ham-Radio-Page/Radial_Project/Radial.htm

Most of the radials will be light guage copper (perhaps 
insulated depending on price), but I don't suppose it would 
hurt to throw in some big conductors for lightning protection. 
So the questions is, what size should I use #4, #2, ??? 
stranded or solid (presumably solid is best), and most 
importantly what is my best bet in terms of price (electrical 
wholesaler, surplus, grand theft (just kidding), etc). 

Thanks,

Mike W4EF......................................................