I haven't really been tracking counties, but the DXLab software I use gives me a count of counties worked/needed.
I assume someday they will accept LotW confirms, but at $.12/QSO that will be pretty pricey! One reason why I've never claimed any WPX awards but I guess I've spent about the same money on DXCC awards overall on LotW, just not all in one check...
73 John K3TN