*rubs hands together*
How fun!
So, some things to keep in mind. We are making a Combo here, which means that we need a coherent Theme/concept and an Effect which matches that Theme. The effects of each rune also have to work with each other.
So what do we got so far for plaque texts?
Warding
To claim the Hammer is to claim the seat of one Lost.
To claim the seat of one Lost is to claim Understanding.
To claim Understanding is to understand the Stone and those born from it.
To understand the Stone and those born from it, is to know thus:
Resist.
Overcome.
Endure.
Courage
To claim the Hammer is to know Truth.
To know Truth is to spurn Falsehood.
To spurn Falsehood is to know Falsehood.
To know Falsehood is to understand the Self.
Resist.
Overcome.
Endure.
Both are amusingly seven lines. It is talking about knowing Truth. Well, there is one Rune, the Left one which not only increases what you got for bravery and also reveals to you things which are unnaturally affecting you. Bravery lines up with what we picked in Worldly Warding (I'd have called it the Rune of Experience or Honed Warding but that's just me), and the revelatory aspect doesn't hinder or directly stop the effects of Warding. This is me saying I think there's a lot of support for Left.
I will also note that looking at this as a case of the runes replacing or standing in for your own abilities or something you can rely on in an unhealthy manner is not accurate here. They boost what you have to start with and give you extra tools to overcome your challenges.
In terms of effects, none of the runes present interfere directly with Worldly Warding's own. That said, from a thematic perspective, this Combo should have both physical and mental components, and more to the point I think it should focus on Will in this choice specifically. The Center choice doesn't qualify based on that alone, because thematically its purely physical and as an effect it doesn't touch on the Will at all.
Dawi are more than just tough muscles - they have Will backing them too. See the Trial of Concealment, see the bar, see Grimnir etc etc.
Right is very interesting because it pulls the combo into a AoE function, like an elder bucking up and leading a bunch of beardlings through trouble. It's a stretch of an effect, but again, doesn't harm or hinder the Worldly Warding and it has a nice theme. With the help of a third rune it might pull on Worldly Warding and extend a lesser form of that rune's benefit to allies as well. That aside, it baseline boosts your bravery and then can be cast to evolve into fearlessness for ten minutes. So resist, then overcome, but then you have to endure the fear on your own/with your allies. Not necessarily a bad choice on this one, but you'd need the Stone option to cover for this - which isn't a bad idea, Warding is covering for certain sources of fear like injury.
But eh. In terms of things we've seen dwarves do, I'd say Left is actually pretty representative - we have an example of it from Concealment when Snorri recognized what was affecting him. This rune would help with that. Left helps you figure out where to direct your efforts, and in and of itself helps you resist (through improved bravery), overcome (through helping you find and destroy the items or sources), and thus endure (by again having improved bravery). There's also an interesting synergy of like, get smacked by a fear causing blade on the armor; the armor and you become more resilient against cuts, and you suddenly cue into where your extra fear is coming from.
Left would also help you understand spells that hit you and cause you fear. Think of a situation where you get hit with a strange spell, and feel nauseous and confused and afraid. Worldly Warding helps you resist that spell and any further magic, while Left Courage helps you identify that it did make you afraid, providing a kind of mental clarity.
I think I'm talking myself around to the idea that there are potential synergies for the second half of left's Effect, basically you have to think em through a little.
I think right or left could work, but I am going for Left.
[ ] [Courage:] Left.
E: SOmething also to keep in mind. Combos do not care about direction or placement of the Runes. Hypothetically, this rune we're picking right now could be Resist, or Overcome, or Endure. Or two, or even all three at once. Using an R+O+E Format I think distracts from the core idea and concept of Dawi.
At least that's how I'm going to be thinking about it.