and well done for finding a Justin thread with no responses ... some doing that
I'll attempt an answer .. though with your background I'm sure you know this ...
The problem with a Major 13 chord is that in theory it contains 7 notes and we guitarists only have 6 strings
the most 'important' notes are the 1, 3, 5, 7, 13 ... 'essentials'
the 9 and 11 are the most 'disposable' ... 'optionals'
I think there are Major 13 chord shapes with just the 5 'essentials' and some with the 5 essentials and either the 9 or the 11 included too ... though I would have to do some homework to check that statement
I'm not sure if that answers your question