Right now wideners has primed lake city brass in stock, don't know how long that will last:
http://www.wideners.com/itemdetail.c...78|282|909|980
Other than making sure your necks aren't too thick (you are cutting 12mm of length off the brass and moving the area to where the brass is thicker) I don't see any problems with it other than a huge time investment.
You don't need magnum primers for Varget in 308. The exception is if you are loading for a semi auto (in which case just buy the primed LC brass and trade off the 30-06 to someone who will use it) then you want a tougher milspec primer. If you use ball powder a magnum primer will also come in handy.
Jimro