Gonna bump this, cause here's my experience with that method so far:
First time I tried this after I read this thread, the reamps turned out aweful. I went so far off the dustcap, that I only had hollow dull-iness.
Couldn't seem to get it right after a few tries, cause I always went too far off center.
So I just stuck to my "old" ways of placing the mic dustcap-meets cone ish, and then move mic-reamp-listen-repeat.
I did a few reamp sessions this way, each time getting to know the cab and the speaker a bit better...been having the Mesa Oversize for about a year now, but didn't have a lot of chance to
do larger reamping sessions to get it to know really well.
So since I felt like now I know a lot better which kind of sound I like from the cab, I tried it again with pink noise this week.
And suddenly it made "click", and I knew what to listen too while moving the mic, and which of the highs are the good, and which are the bad ones.
That was really hard to hear the first time I tried it, cause I couldn't relate it to how it would sound with a guitar playing.
I tried it like 5 times, each time the mic looked like it was placed really really similar, but it never sounded 100% the same. But pretty nice, most of the time.
Really neat method to get you in the ballpark with a nice starting point, or even with a position that doesn't need any more tweaking.
Altho I don't think that this last session overall turned out "nicer" reamps, it was certainly easier and didn't take as long to get it where I wanted it.