Once you have both sets you'll be able to switch them out and see what fits best, and generally I've found its a decent way to make your jewelry universal for all classes. I would recommend creating (since you're talking end game, yes it will probably take a while to do) a set of vitality/ability/crit/critd rings and neck, all the same 4 stats, and then a set of power/haste/crit/critd. I don't however put it on my gear, I'll use it on gear dropped that's an upgrade, but as far as end game crafted gear I won't. However it is widely done, and I myself have a full set of power/haste/crit/critd jewelry and use it often. So I don't see the point in putting it on end game gear. I'll discuss power next but you'll find that I disagree with actually putting power on much of my gear, since technically there is no end game for power, it just keeps going. vial of Wind Spirit, hailstorm, for ability the integralas mantle etc., Or go with a comfortable or more self desired stat rate (I like at least 6 to 7 hits per sec as opposed to the more popular in some cases minimum required to properly utilize haste of about 4 to 5 hits per sec)(I prefer around a %50 increase to ability rate whereas most prefer %65), after ability rate it gets a little more class/gear/play style/PC or mobile related. The most important stats being (not in order of importance necessarily) haste for your hits per second, you need to decide whether you're gonna go with the bare minimum, keeping in mind all of (more variables) your other gear that would increase these stats, i.e. Meaning that you need to be thinking about the end result of your overall stats while deciding what to put on jewelry/gear. The result you want to base these decisions on will be shown in your stat page in the inventory screen. Meaning it depends on the 4 stats you ( assumedly) are putting on your end game gear.

Generally your rings will balance your gear. There's really more contributing factors to be discussed in order to accurately answer your question.

Eternium jewelry crafting