Well, when teaching formation flying in our PA28s, we also teach breaking formation to join the circuit. No high energy manoeuvre this, it is simply a level turn from the deadside onto downwind with each aircraft in the echelon delaying the break from formation by the briefed interval.
The AoB and interval used for the break must be the same for all members of the formation; you can start with a gentle 30 deg turn at 5 sec spacing and, as experience is gained, tighten it up to about 45 deg and 3 sec.
There should be no need to use more than about 1.4 g to break a formation of light aeroplanes into the circuit.