I think primary is overkill for Lewinsville Road/Great Falls Street, same with Spring Hill Road. SR 694 kinda just straddles the area between Tysons and McLean and bypasses anything of signiciance like a major commercial area like Tysons Corner or the Chain Bridge Road/Old Dominion Drive junction in McLean, while Spring Hill Drive doesn't serve much as a major road either. Secondary would be ideal for both of these roads.