The diffuser lenses spread the beam from a narrow 8 degrees to about 30 degrees, which should help with taxiing.
With your setup I'd put one on each side, whereas a tail dragger would likely put them on the one light that is aimed lower.
I'd recommend you try the lights without the diffusers first. If you're happy with the available light during taxiing then leave them off. All the more light reaching further ahead for landing!