The volume Simple English Propers gives the attached verses from Psalm 8 as the verses for the Offertory of the Transfiguration. You could find the analogous verses from the Vulgate and set them to Psalm-tone I (to match the mode of the antiphon).

O Lord, our Lord, how majestic †
is your name through all the earth! *
Your majesty is set above the heavens.
From the mouths of children and of babes †
you fashioned praise to foil your enemy, *
to silence the foe and the rebel.

When I see the heavens, the work of your fingers, *
the moon and the stars which you arranged,
what is man that you should keep him in mind, *
the son of man that you care for him?

All of them, sheep and oxen, *
yes, even the cattle of the fields,
birds of the air, and fish of the sea *
that make their way through the waters.
O Lord, our Lord, how majestic *
is your name through all the earth!

Thanks, RR.
I was hoping to find the more melismatic, but these will do just fine.

I too need this, for Gloria et divitiae

(It was in 2015.)