You, FTB and I share a disposition toward similar sleep cycles. Every person has an internal clock effected by light/dark/moon etc and they tilt one way or the other (morning person vs night owl). If the FAA/airlines were really interested in safety they would work harder at creating pure AM and pure PM flying that consistently maintain either early show times or late show times but not a mixture of both in one trip. No such luck though and a missed opportunity during the part 117 rule implementation. Let's go ahead and add one more fatigue inducing flights to the list though. That ought to help.

Circadian Rhythm Disorders: Shift Work, Jet Lag, and More

Delayed Sleep Phase Syndrome - What It Is And How To Treat It

Another interesting study, rats that were denied any restorative sleep for many days, simply died. Any time you cut into the natural restorative sleep cycle you start asking for health and safety issues.

Sleep deprivation in the rat: III. Total sleep depriva... [Sleep. 1989] - PubMed - NCBI

"Ten rats were subjected to total sleep deprivation (TSD) by the disk apparatus. All TSD rats died or were sacrificed when death seemed imminent....No anatomical cause of death was identified. All TSD rats showed a debilitated appearance, lesions on their tails and paws, and weight loss in spite of increased food intake. Their yoked control (TSC) rats remained healthy."