Complex sentence: Russell travelled to London, where he screen tested Liza Minnelli wearing a blonde wig and custom-period gowns; he felt that, Minnelli, a more established film actress, would be perfect for the role.
Split into simpler sentences: Russell travelled to London, where he screen tested Liza Minnelli wearing a blonde wig and custom-period gowns. He felt that Minnelli, a more established film actress, would be better suited for the role.