Sir i really dont know how to do math like this, i'm really bad at math, good at solo content only. Beside i only do it once, not spamming dungeon for set. That's why i need to askMhhh - I could try to explain that to you, but I smell a trap here.
You are the guy who postet vids of solo vet HM and you should have all pieces to test that on your own.
I'm only able to solo normal falkreath hold, so that means your knowledge is probably much higher then my.
And so I feel bad to explain you a delay before the proc hits (and so that at least in PvP your oponent can avoid the proc) and a DOT...
OK
I'm no DPS guru either and I play PvP only, but I did a short test how often Nirn is proccing.
So the inital part is hitting after 1 second.
Then there are (unavoidable) DOTs every 2 seconds for 5 times before the proc can start again.
So I would say your calc should be (4718+23590)/11.
If the enemy has another DOT ticking, the next tick will trigger Nirn again.
(This can go to an extreme where you can use sets which are proccing each other and I was able to kill a 6M dummy with one LA)
So if you use a 12 second reflecting light, Nirn will proc a second time IF the enemy stands still when it procces.
Then I got the second proc almost on point and I had 2 procs in 21 seconds. (5 procs in 52,5)
So I'm not sure how real DPS calculation would do the maths for something like that.
Maybe (4718+23590)/10,5 ?
However - The DPS is not reliable, because if you hit an enemy the pillar will spawn where the enemy stands.
If the enemy is e.g. walking/jumping towards you, the pillar is often not hitting the enemy at all (thats what happen in PvP almost always if you dont find a combo which include a stun) because of the small radius.
Then you do no dmg for the whole 10 seconds.
Ofc. the same will happen if the enemy dies early and maybe you are not able to control allways where it procs and you could hit an add instead of the boss.
I used Syv+Nirn+Selestrix for that.
The first LA triggers all sets and then they proc each other till the dummy is dead
I tried that one day in Cyro and during keep fights you can hit somebody at a siege or at the wall and sometimes it worked there too.
But for real usage, it was the best to trigger Nirn with a DOT like the templar skill or entropy from the mage guild - then you have a chance of a second proc, if the first proc was successful.