My hips come down off-center when I squat (and wind up pushing more with that leg). Unilateral stuff didn't help at all... only thing that seems to work is to put conscious effort into bringing my hips down centered (which to me feels unnatural but playing back videos, looks centered).
I know Charly started using a red one. We have all of them at our gym but only started using the blue one before my last meet for some overload work after my main sets. After a couple sets, feels surprisingly natural.