Richard,
The web address didn't work for me.  Solid, stranded, braided, all 
the same when you put it in the ground.  Sixteen gauge is, yes, 
better than 18 gauge.  Insulated may not disintegrate quick as soon 
as bare.  I didn't see the price.  Do you have a way to conveniently 
get to Home Depot or the like.  Check their price on #14 or $12 house 
wire.  Might be less expensive than the Amazon product.  And now that 
I think it through, perhaps stranded would be a bit easier to work 
with than solid.
But whatever you decide on, the more the better within reason!
Pat, K9JAUAt 12:03 PM 7/4/2014, you wrote:
>Hi!
>
>
>
>See the below Amazon link for this 16 gauge copper wire I am thinking about
>for use in making radials for a vertical antenna.  16 gauge is thicker than
>the 18 gauge recommended by MFJ for radials, so I like that.  However, 1)
>this wire is "stranded" versus "solid" and 2) "insulated" versus "bare".  I
>am not sure if "stranded" is the same as "braided", or if it matters if
>radial wire is solid/stranded/braided.  Also, I understand that it does not
>matter if the wire is bare or insulated.  Is this true?
>
>
>
>http://www.amazon.com/Coleman-Cable-16-100-16-16-Gauge-100-Feet/dp/B000HAB82
>M/ref=pd_sim_hi_1?ie=UTF8&refRID=12AN8JXN3WW2KME3BT1X
>
>
>
>73,
>
>Richard KK6MRH