>>63883922The golden number is between 3 and 4, depending on how independent the element needs to be. 2 is only ever the number for extremely complex command environments (eg a Tk Pl where the two sections will usually be miles apart, the tactical situation is dynamic and very fast, information is scarce but valuable, and the commander must also command their own vehicle), but even then they go to 3 or 4 as soon as they can at a higher level (eg a Tk Coy is still 3 Pls).
4 is almost universally preferred for fighting, but the rub for organisations like the CAB and ABCT is that they usually get atts beyond the orbat and even when triangular start with slightly more than 3 elements to manouevre (eg the Cav Tp and CE Sqns in the ABCT, which both develop combat power and conduct manouevre, even if it isn't their primary role). When you see these 3 element organisations, it's almost universally because they're meant to get a fourth attached for fighting - eg two of the three CAB in the triangular ABCT are expected to get a CE Sqn attached in the assault, the third CAB will absorb an infantry company from somewhere, and an Aviation (Attack) Bn/Coy will probably get attached to the ABCT for reserve or SBF, or the Attack/Recon Bn or a Coy from it will be attached for flank security/reserve. But the whole thing is a game of musical chairs, since that means the Div then ends up triangular, and so the musical chair game continues with higher assets again.