This is the part to read before you build a 2,000-point list, because the list in question is the one your models point at.
Solar Spearhead (2 DP) + Might of the Moritoi (1 DP) costs exactly 3 DP, a full Strike Force budget, and it is the obvious walker list: the armoured detachment plus the Dreadnought detachment.
It is illegal. Both carry the ARMOURY tag, and no two detachments in your army may share a Unique Tag. Faction Pack v1.1 states the tag inside this detachment's own rule text, and the Munitorum Field Manual v1.3 and Wahapedia both record UNIQUE: ARMOURY on both detachments. No source disagrees.
And here is the part that makes it a genuinely good design rather than an arbitrary restriction: the rules would not stack even if the tag did not exist. Solar Spearhead's second detachment rule, Moritoi Ancients, reads add 2 inches to the Move characteristic of models in ADEPTUS CUSTODES WALKER units and add 1 to Advance and Charge rolls made for such units. That is this detachment's entire rule, reprinted inside a bigger one. You would be spending a Detachment Point on something you already owned.
Games Workshop signposted it twice. Both detachments print a 1CP stratagem called Flawless Construction with near-identical wording. They are alternatives.
So the real decision is which, and it is a real decision:
- This detachment at 1 DP if walkers are a component of your army and you want 2 DP for something that solves a different problem.
- Solar Spearhead at 2 DP if the armour is the army. You get this rule for free inside it, plus vehicle-wide Objective Control and re-rolls, six stratagems instead of three, and the Keywords rule that turns up to two Walkers into Characters so a Telemon can carry Augury Uplink for a 5+ Feel No Pain. Nothing else in the faction does that.
We never suggest the pairing anywhere on this site, in either direction.