Just some napkin math. Thinking about the theoretical maximum uptime of SotR. If we presume 50% haste aswell as pvp 4p bonus with DP.
In a 10 minute fight.
We would gain, 200 hopo from CS, 138 from judgement. Have 24 GC procs on average from the CS. Recieve 400 boss melee hits, so lets assume a low 20% dodge/parry. You would then dodge/parry 80 attacks which would give another 7 or so GC procs, but for the sake of overlapping lets say 6.
So we are looking at 368 HoPo gained from attacks. 4p would be another 67~ +- depending on the boss design Holy Power. So in total we are looking at around 435 holy power gained. Give or take 10-20 depending on boss design and stuff. That is 145 SotRs.
With DP. That would extend to about 48 DP procs give or take a few depending on rng. So in total 193 SotRs. Which would be equal to 579 seconds uptime. That is 579/600 seconds uptime or 96.5%. So, it is pretty safe to assume that above 90% is fairly easily reachable if you go for max uptime. And closer to 100% would be obtainable with some luck on procs.
Interesting interesting. To bad that the PvP pieces are so low item levels this tier, this was far more useful last tier. It is a serious dent in stamina and armor to take on PvP pieces, but the set bonus is insane for constant streams of damages during an entire fight. So if a fight lacks that "AHA IM GONNA KILL YOU NAOW! ability, it could be worth having a 4p set in the bags.
The 4p alone is equal to about 14% uptime.