lol, Condor +2 (Occ. Double Damage version) is not better than Gandiva. Jishnu's Radiance is much stronger than Sidewinder, and even more so in Abyssea. Since you're also not going for crit atmas, Dead Aim is going to be useless for you, but give Gandiva user's 40% more damage on crits and with high crit rates in Abyssea, aftermath will be procing on those crits quite a bit. The only way you could have outparsed a Gandiva RNG is if they were sleeping.

Edit: I think using Unlimited Shot with Barrage shouldn't be changed. But reduce the cooldown to something like 30 seconds so we can abuse the sweet spot enhancement off of it. To me, it doesn't make sense for them to stack.