When is it appropriate to sing the Pange Lingua?

Hi all—
I'd love the hive-mind's opinion on this: when is it appropriate to sing the Pange Linga (if ever) outside of Corpus Christi and Maundy Thursday?

Some hymns have very strong associations with only single days of the calendar, and this seems to be a candidate for such. (I confess, for many hymns, I bend the rules and use them at other times, too, or use alternate texts with those tunes. I use IRBY with the text, "Wondrous Love, that cannot falter" during communion, for instance, otherwise we would only hear it once a year at lessons & carols)

That said, I had the idea to use the first verse of the Pange Lingua for All Souls, and I was wondering if this is just too weird.

We use AntiphonRenewal's entrance antiphon tropes, but the meter for this week isn't conducive to any good, penitential-sounding tunes. It occurred to me that we could sing the first verse of the Pange Lingua (which is fairly appropriate for a requiem mass) and then an alteration of the options AR provides, such that it would be:

Sing, my tongue, the Saviour's glory,
Of His Flesh, the mystery sing;
Of the Blood, all price exceeding,
Shed by our Immortal King,
Destined, for the world's redemption,
From a noble Womb to spring.

Requiem aeternam dona,
dona eis Domine,
Grant them everlasting rest, Lord,
on them shine your light alway.
Blest the ones whom You have chosen
ever in Your courts to stay.

The end result would be praising God for His Sacrifice, and then a trope of the Requiem Æternam. Seems fitting to me, but I won't do it if this is just too off-the-walls.

And this peculiar situation aside, do any of you schedule it for any other time of the year apart from CC and MTh? I imagine some of you schedule it for communion, but to other tunes, rather than the chant melody.