I did play with the delay of the subs based on what Tom wrote at PSA where he said you should add about 1msec delay for every foot away the sub is from you. So I have 1 sub that is 3 feet away facing me and 1 sub in the back left corner that is 9 feet away so I did adjust that. Can't really tell if that made a big difference though.
Of course not. Because he's full of it. The one foot per millisecond is based on being approximately the speed of sound in air. One foot per millisecond.
There's a couple times this matters. One is side wall reflections. Side wall reflections that arrive within about a 3 to 5 ms window of the direct sound have a very bad effect on imaging. That is why we want our speakers a good 3 feet away from walls. The other time is with movies. If the screen is several feet closer or farther away from you than the speakers then the people talking on screen will be out of synch. That's it.
This rule of his is not applicable to subs for the simple reason human beings cannot even hear low bass at all, at less than a full wave. Since a 20Hz wave is 1/20th of a second that is 50ms before we even hear it. So when it comes to subwoofer bass you can forget about timing. Its simply not a factor.