While Livesplit has the time at 15:59:00, there was an FMV skip that occurred after the fight with Diamond Weapon (at about 9:44:00 into the video), which resulted in me inadvertently saving about 57.69 seconds.

This was the second completed run of my current grind. While no individual thing went catastrophically wrong, I still lost over 10 minutes to execution issues over the course of the run. Cleaning this up as well as incorporating better routing suggests a target time of about 15:45 is now viable.

Mod note: the 58 seconds added to submission vs RTA time is accurate and verified.