Under optimal circumstances - with full and direct parts/logistics/support, you will never see more than HALF a squadron of foreign F-16s operational on a good day.
Ask anyone who's tried it.
Two aircraft flying a CAP over Kyiv during daytime hours and in good weather, two more on strip alert so libg as the pilots arent too drunk to fly. Much more than that and Putin destroys the runways of wherever they are based anyway.