My experience is that 2-3 songs into an audition they've likely already decided in the minds if they like me (you) or not.
Auditioning for 5 hours seems insanely un-necessary. Hell, I wouldn't PRACTICE for 5 hours with any band I've been in for the past 15 years.
Also... height, weight, appearance issues quickly dissipate 30 - 45 seconds into a show if the band truely brings it and plays like a band. The 'oh **** these guys kick ass' factor is a great great equalizer. You run into that ALOT here in the Nashville. You can wander into some place with a band and never know what kind of talent will be on stage.