Topband: Optimal radial wire type and gauge?

[Rick Kiessig]

The recent talk about optimizing the number of radials has me wondering
about the optimal type and gauge for radial wire. I've been using #14
stranded, insulated copper, but for no reason other than it's readily
available in 500 ft spools at a decent price. With the cost of copper being
so high these days, is there a better choice? If so, how do we know it's
really better? And is there an easy way to trade off cost vs. effectiveness?
I can't use mesh at my QTH, so I need to stay with actual wire.

 

73, Rick ZL2HAM