I'm a firm believer in do not throw the other toggle. Flaring with one riser and one toggle is not difficult. Not only is the canopy easier to control, it it will shut down with greater ease. Prepare to PLF and do so if necessary.

Flying with just rears with the brake lines trailing, is challenging. The ability to fly slower than full flight no longer exists. The control stroke is very short. Commonly people never practice riser or riser/toggle landings until a line releases for whatever reason.

The usual scenario for over control is as follows.

When both toggles are gone, hopefully the landing zone is large enough to accommodate. Fly to the landing zone at full speed, at 10 feet, flare too hard. The canopy first plains out then stops, stalls, and falls/flies backward. The jumper is traveling forward so he is not under the canopy yet. The jumper then falls directly onto their back from a much greater height than expected. In my experience of watching people do this, it's usually around 6 to 8 feet. That's a big fall to just back flop. Take into account the terrain. Take a back drop into rocks or rebar ... You get the picture.