Not many. The A-8/R8 was to carry a 20mm frontal shield with small 4mm upper and bottom shields. (4mm is no protection at all against .50 cal.)
Moss
Unfortunately you have forgotten about adding that there was a big radial engine in front of the frontal shield .
Here you are more on the subject.
Here is the standard armour set for Fw190A.
5. the windshield 50mm armoured glass.
8. a back of pilot seat - armoured plate 8mm
9. armoured plate behind a pilot's back - 5mm
10 two armoured plates mounted to the cross-section no.5 - 5mm
11 armoured plate behind a pilot's head - 12mm ( 20mm for A-8/R8 )
In addition.... A-8/R7 and A-8/R8 had mounted the armoured basis of the windshield -15mm, two triangular armoured plates of 4mm on both sides of the windshield basis, the horizontal panel in front of the basis - 4mm.Two 30mm armoured glasses of the windshield sides.
For sturmbocks there were added two armoured plates outside of the cockpit - 5mm and 30mm armoured glasses on the slided cockpit conopy.