Call of the Brotherhood: To wear two or only one?

My question is: Do you think its better to wear one or two "Call of the Brotherhoods"?

To my understanding, the "has a 100% chance to shock against Frozen enemies" will not apply if you wear two rings because Shock duration is based on "Lightning Damage Dealt" and if you have 100% conversion, your shocks will last 0.00 seconds due to no Lightning Damage being dealt. If that's wrong, feel free to correct.

Assuming that's the case, here's what I think using one or two would have:

Using Only One
*You'll have 50% Lightning and 50% Cold Damage converted from Lightning
+You'll get the effectiveness of the 100% chance to shock, dealing more damage overall to shocked enemies.
-Using either Lightning Pen or Cold Pen would not be super effective as you're dealing a mixed damage, and using both isn't the best use of sockets either

Using Two
*You'll have 100% Cold Damage that was converted from Lightning
-You wont be able to take advantage of the "chance to shock" as you deal no Lightning damage to shock.
+You can use Cold Pen easily

Since either choice isn't going to matter much against your regular Whites and Blues, the real question is which is better against Rares and Uniques? With so much health, are you even going to shock most Uniques or even Freeze them in scenario 1? Do you have a better chance converting all your Lightning to Cild and using Cold Pen to freeze? In Scenario 1, do I even bother with using Pen at all since its only 50/50? I'd suggest Ele Weakness curse, but curses are already nerfed on Map and Story Bosses that it wouldn't be as useful as Cold/Lightning pen.

So what do you guys think? If any of you have used Call of the Brotherhood or have any idea which is better in the long run, let me know. Thanks

Though I guess it would be better for the Freeze to make sure Cold Pen is on even if I used only 1 Call of the Brotherhood. Maybe i'll try that first, but I still want to hear what people think.