Which canning element is safe for my range?
The canning element WB30K5019 would be the correct element to work on your unit.
1.What advantage is there for using a canning coil element on an electric range.
2. Can steam canners and large pressure cookers be used on glass topped electric ranges without causing any damage to the heating surface?
The advantage of a canning element on an electric range is that it does not trap heat and cause hot spots. As far as a steam canner or large pressure cooker being used on a glass top, it is not recommended unless the pot is no more than a 1/2" bigger than the element. If the pot is too large it will cause thermal breakage of the glass by trapping the heat.