Re: your opinion of "Wheat Pennys"
As with anything else you can deduce from empirical observation, the presence of wheats at a site may indicate your "in the zone" for silver from that period as well. But then again, remember how many wheaties were minted, and their ratio to silver, visibility to "eyeballers" past and present and you can see why there might be some sites where wheats so dominate while silver really eludes the hunt. Yep, love digging them as much as any coinage.