If the fasteners are torqued tightly enough that load is carried by
friction in the joint rather than shear, the fine thread again has the
advantage because its greater root diameter makes the bolt stronger in
tension, allowing it to apply more force to the joint.

Among your choices, the 1/4-20 is strongest; a 1/4-28 would be
stronger still.

Well said. (I think he stole my answer!!! har har)

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