Complex sentence: Siegel later estimated that Totten had spent 25 days filming and he had spent 9-10, with roughly equal footage in Siegel's final edit, but he made it clear that Widmark had been effectively in charge the entire time.
Split into simpler sentences: Siegel later estimated that Totten had spent 25 days filming, and he had spent 9-10, and each had roughly equal footage in Siegel's final edit. But he made it clear that Widmark--rather than either director--had effectively been in charge the entire time.