I also tried @Knottewe slotting just in case there was gold lurking in there (two 50++ Acc/Dmg HO and four procs), but since we lack a fourth damage proc I slotted Achille's Heel in the other attacks and a Decimation chance of Build-Up in Proton Stream. This of course added little more than more theoretical upkeep on Achille's Heel. Not having any end reduction slotted was immediately noticeable as the passive recovery + Defensive Opportunity could not keep up, but it wasn't a problem since the endurance clicky of Ninjutsu kept things stable.
Hasten also took a dip to 132 seconds so I used Ageless in the testing... but only got 3:49 seconds. An improvement for sure but not one I would chase. It would be a different matter if I could finagle a fourth damage proc but I couldn't find one. Non damaging procs are a possibility though. the Winter's -recharge and slow is a defensive option as well as the -ToHit but....
Does SNBR track Decimation procs? Someone tested with a T1 and it apparently seldomly procced, which is why I tossed it at Proton Stream also thinking f it feeding Atomic Blasts.
Edit: Post breakfast thinking about slotting in four procs. Now fed I can see I could have swapped Apocalypse to Cosmic Burst instead of a third -res. Also, Cosmic Burst could take the Gladiator's Fury -res and that being replaced by any of the damage procs in Atomic Blast. Apocalypse in X-Ray Beam feels like a waste though but it can be easy to test in justin:
Proton Stream: Javelin proc, Touch of Lady Grey proc, Achile's -res proc, Decimation proc.
Cosmic burst: Shieldbreaker proc, Touch of Lady Grey proc, Javellin's proc, Apocalypse/X?
X-Ray Beam: Shieldbreaker proc, Touch of Lady Grey proc, Javelin's proc, Apocalypse/X?
This is definitely entering pylon killing chasing territory though. For regular play I would not advise -res procs in our hardest hitting hitter, or Apocalypse in our weakest attack. When do we even hit the same target for four minutes at a time? Regular play is about burst and we would want our Proton Stream to kill a mob instead of it surviving debuffed but with a sliver of HP and requiring a second skill to finish killing.