Michael Lagoudakis wrote in discussion forum byzantinechant:

1. TEXT

The full text of all lamentations along with the verses of Amomos (as they
should be chanted) can be found in the Triodion book in the Orthros of Great and
Holy Saturday.

There is a wonderful site with all the Greek liturgical books available online:

http://www.tcgalaska.com/glt/

So, clicking on the appropriate link:

http://www.tcgalaska.com/glt/texts/Tri/t97.htm

you get the text for Great and Holy Saturday. Scrolling a few pages down you
will find the text for the lamentations. All other publications (Papadeas, etc.)
contain only a subset of these and commonly without the verses.

Notice the proper place of the lamentations in the Orthros; very early on.
Unfortunately, parish practice has moved them later, close to the end of the
service; my guess is that this was done so that even those who arrive late get
to hear them.

2. MUSIC

Here is the traditional music from the Holy Week book of Georgios Raidestinos:

http://www.isye.gatech.edu/~mlagouda/SHARE/LAMENTATIONS/lamentations1.jpg
http://www.isye.gatech.edu/~mlagouda/SHARE/LAMENTATIONS/lamentations2.jpg

For each stanza, he provides the fast heirmologic and the slow heirmologic
version. You probably want to focus on the fast heirmologic which is the most
common in use. The slow heirmologic can be used for concluding each stanza, when
the first troparion is repeated at the end.

3. ISON

1st and 2nd stanzas: With the (proper) ending on Di, the ison can be on Pa or
Di, but certainly not on Ke. With the (unfortunate) ending on Ke, the ison again
should move to Pa (notice that Ga is natural in this ending).

4. RECORDING

Check out this recording from the Vatopaidi Monastery:

http://www.isye.gatech.edu/~mlagouda/SHARE/LAMENTATIONS/lamentations1.wma
http://www.isye.gatech.edu/~mlagouda/SHARE/LAMENTATIONS/lamentations2.wma
http://www.isye.gatech.edu/~mlagouda/SHARE/LAMENTATIONS/lamentations3.wma

The files are somewhat incomplete, but you will get the idea.

In these recordings, they sing the fast heirmologic version of the first and
second stanza and the slow heirmologic version of the third stanza. With some
minor variations, their music is the one found in the Raidestinos book posted
above.

I am sure there are many recordings out there, but this is the one I have
available right now.

5. TODAY's PRACTICE

Unfortunately today's practice (very well recorded in Stan's music) has deviated
a lot from the above. In particular,

1st Stanza: It became a mix of slow heirmologic (phrase "katetethis Christe")
and fast heirmologic (the rest of the hymn) with an incorrect ending on Ke.

2nd Stanza: It became a mix of slow heirmologic (phrase "Axion esti") and fast
heirmologic (the rest of the hymn) with an incorrect ending on Ke.

3rd Stanza: It ended up being just the second voice (parallel thirds) of a
harmonized variation of the traditional fast heirmologic version.

The verses of the Amomos are not in use any more and only a selection of about
10 lamentations from each stanza is chanted in most US parishes. At many places,
the traditional practice is slowly restored. At my parish in Thessaloniki,
Greece we used to chant (children choir) 33 hymns from each stanza in the
traditional melos (see Raidestinos above) along with the verses. Also, I recall
that at the monastery of Panagia Pammakaristou in North Carolina we used to
chant all ~300 lamentations. However, I am not sure if there is any parish in
the US chanting more than the Papadeas selection.

6. MY RECOMMENDATION

Samuel, I think the best you can do for now is to use the popular today's
versions of the lamentations (as recorded in Stan's music with your suggestions
for ison Pa and no harmony in the 3rd stanza). It will be hard to do anything
else because it will conflict with what people are used to; at the end of the
day you don't want to cause problems on such a Holy Day.

On the other hand, it's good to constantly educate ourselves, to know what
exists out there, how it should be and how it currently is, so that we are not
misled to believe that we are correct or perfect.