Now days I think it's better to only have one toon/class, unless you want a couple different healers or tanks. For DPS toons, just train them up in both stam and mag and reformat as needed.

I have only seven characters. All of them has more than four hundred skill points and ten armory slots. So switching roles is just one click away. All gear stored in bank as well. So i can just put my desired gear on a character with addons.

I would recommend using damage dealer Arcanist as a separate character. Other one can go with Healing and Tanking as some of the passives are both needed for those roles.

I usually go for mag/stam dps, but in some cases I have a third character for a healer, tank or for PvP, or I swap one of the specs for a healer or tank. For my two arcanists I chose the stam spec as dps, and the mag spec as a healer, and I like how they work so far.

I have one build per character and will never use the armory for anything other than a furnishing. I hate the idea of always changing and remembering what build I'm using, and do not want to carry gear sets around with me. Plus, since I will never play a tank or healer there is really no reason for me to use it.

I don't have the armoury at the moment. I have access to a North American server where I currently try different builds. If I like them I recreate them in Europe.

I make them originally one way, the 2nd slot is an afterthought. Like my NB dps was a stamblade but then I wanted a healer/magblade. So I just used the DPS in question because both setups fit him. My arcanist I have all 3 pve roles on because I didn’t get around to making a 2nd arcanist. My goal since armory is to have a mag dps, stam dps, tank, healer of every class using armory but its not gonna happen.

Generally it works to use a Stam DD as a Tank and have the Mag DD of the same class as a healer.
With the Armory System it is easy to swap those two specs.

But to drop some criticism here, there are classes where the Stamina and Magicka setups play exactly the same!
Templar, Nightblade and Arcanist use the same spammables, the same DoTs and the same support abilities.
There is no difference in the rotations. None at all. They all feel identical.
So, if you use a hybrid race, like Khajiit or Dark Elf, you will not be held back by that. In these three classed, I only need one character each for all three roles.

Dragonknight is almost the same. You would only use a weapon spammable on the StamDK, instead of Molten Whip. But theoretically you could do so anyway. And so MagDK and StamDK feel the same again. However DK as a Healer is ... well, let's just say you will face challenges, that other classes do not.

When I had only two slots, I would have one damage and one support role. For stamina characters, they had a stamina damage build and a tank build. For my magicka characters, they had healer and magicka damage.

Nowadays, most of my mains have 5+ armory slots, usually with the following loadouts saved:

1. Magicka Damage
2. Healer
3. Tank
4. Bow/Bow
5. DW/2H
6. PVP or Bash
7. Skill Reset