Had a little play yesterday, firstly i only use the rears for a bit of sound fill.
May be music dependant ie the recordings, will have to try something else.
As is i have set front right 0.5ms, rear right 0.2ms.
In a funny round about way its more like adjusting the left right balance, but only any good for one specific seating position.
On the front right ok from 0 to 0.7ms delay, any more it sounded awfull. Good choice for me is between 0.4 and 0.6ms top whack.
We dont have this for home hifi, no balance, tone etc, we sit right in the middle to get the best soundstage and stereo imagery.
Even with the best Dynaudio, some branded as KEFS and Genesis, only offer glimmers of soundstage in a car.
More testing required but worth while in a car for one person.