The lugs for the caliper are on the front of the slider, and the sliders are handed, so no simple way of getting the caliper to the back.
With modern pad materials which need to heat up to work there little advantage in six piston calipers with large pads which were beneficial in the days when you wanted the pads to stay cool.
Some six pots now actually have three small pads with less pad area than some twin pots.
Which is why they have almost vanished from new bikes.
Mechanical advantage comes in to it too, but six 30mm pots have minimal advantage over two 50mm ones.
FWIW I have fitted a six potter on my GS to no great benefit, which I will probably remove one day, and have improved the breaking on my G/S by removing a PO fitted four pot and reverted to a OE twin pot for a noticeable improvement, so this is not just second hand theory.
As I recollect that bike was made to the owners spec, so no reflection on the fabricator intended-------.
