The Guitar Player article (two, actually) focuses on one particular
sequence
of notes, 5-6-b7-6. Relative to an A7 chord, this sequence would be E, F#,
G, F#. If you put this sequence in the bottom voice of our aforementioned
6ths, you'd want to voice them this way:

e-----------------
B--2--3--5--3-----
G-----------------
D--2--4--5--4-----
A-----------------
E-----------------

This gives us the 5th(E) and Major 3rd (C#) of the A chord, the 3rd
(F#) and
root (D) of a passing D chord, the b7(G) and 5th of the A7 chord.

If you put the 5-6-b7-6 in the upper voice of our 6ths, you'd have this:

e---------------
B--5--7--8--7---
G---------------
D--5--7--9--7---
A---------------
E---------------

This gives us the b7(G) and 5th(E) of the A7 chord, the root(A) and
6th(F#)
of the A13 chord, the 9th(B) and b7(G) of the A9 chord. The A and F#
in the
second voicing could also be heard as a passing D chord.

To use this for a V-IV-I progression, often seen in the blues, you
might see
this type of phrase:

E9 D9 A9
e--------------------|--------------|------------|---------
B--12--14--15--12\11\|10--12--13--4/|5--7--8--7--|-5--7\5--
G--------------------|--------------|------------|---------
D--12--14--16--12\11\|10--12--14--4/|5--7--9--7--|-5--7\5--
A--------------------|--------------|------------|---------
E--------------------|--------------|------------|---------

or this:

E9 D9 A9
e--------------------|--------------|------------|---------
B---9--10--12--10--6\|7---8---10--8\|2--3--5--3--|-2-------
G--------------------|--------------|------------|---------
D---9--11--12--11--6\|7---9---10--9\|2--4--5--4--|-2-------
A--------------------|--------------|------------|---------
E--------------------|--------------|------------|---------

Questions?