I don't see any problem on doing /sam at Bahamut 2 and ending first on pase with a RC anyway, just wait for 1 warrior to voke and hit before you get on your first hit. For Vrtra i do understand the implications, i got terrorized at the beginning, lost around 10s there and came out second after another DRK who altho was /sam too, but didn't get roared or charmed, but died at the end.
Anyway, since you in your charts you are talking of perfect situations, you should do 2 things, first add a perfect KC situation (8 hits/round with 95% acc) which is almost as impossible as capping pdif with RC on Vrtra or Kirin. And second, extend the damage until 1 minute and see the implications of losing Desperate Blows and a Cure bombing situation for the 30 remaining seconds of SE, because Vrtra and Kirin at least don't go down on 30s, well at least not with my LS since we don't have that many DRKs (or any KCs at all).
Also for your optimum gear set up what about Homam body in place of Gloom. Im just a little curious as to how big a difference Homam body would be to Gloom since it does offer Triple attack enhancement, HP and, accuracy.
You most likely don't require Acc+ (since why you usually should eat Carbonara +1 and not Sole Sushi +10) if you are doing it right, then you will have Madrigals on.
Homam gives you 28 HP, GB (assuming 2k HP) gives you 40 extra damage, 12 more than Homam, and with the more HP you have, the better.
Regarding Triple Attack, if you are using Brutal Earring, or a multi-hit weapon, then there will be a conflict and you will lose at the end when every hit is being decided as multi-hit, DA or TA. Stick to DA or to none at all.