It seems pretty clear to me that Richard means that ... would prefer to spell as "aw" rather than as "ah". Why he would want to spell it "aw" passes understanding, since he has also implied that "aw" may be

If you say that to me, you say nothing. As a description of a sound, "aw" has no useful meaning. But I think it does have some useful meaning to the community of CINC AmE speakers. I think if you were CINC you'd understand. I doubt

Indeed, that's what we CINCs have been saying all along: your "ah" sounds like "aw" to us. If you say that to me, you say nothing. As a description of a sound, "aw" has no useful meaning. It seems pretty clear to

If I want you to use the vowel of your ... order to accomplish that? What would you suggest I write? Before I made a suggestion, I would want to be persuaded that there was some good reason for you to want me to use a vowel when you don't know