Consider this passage from Manciolino:
Beginning, therefore, the second assault at its first part, which is going to the play, I say that similarly you will settle yourself in one corner of the room as you did in your previous graceful arrangement, and you will cross toward your right side with your right foot, striking the dome of your buckler with the false edge, and raising your sword into guardia alta, so that your buckler is turned toward your face in the manner of a mirror, and thence you will pass forward with your left foot into large pace, making a great leap toward your enemy, in which tempo your sword must make a tramazzone into porta di ferro stretta, and thus you will abide with your feet even.
Both Ilkka of Maroozo.com and the fine gentlemen of Academie Duello interpret this as looking at the front of the buckler. And while I usually defer to them on matters of interpretation, here I have doubt.
Is it not true that a mirror has two sides? And is not the back side of my buckler is just as flat and shiny as the front side?
When in my vanity I gaze upon my own reflection, I desire to hold my buckler outward. In such a fashion it not only rebounds my visage to my own eyes, but protects my eyes from the loathsome and ill-favored features of my foe.
Were I to hold my mirror close so that I may gaze at the front, its surface would not cover but a fraction of my beauty. Held far, I can see all of illustrious self.
So when I hold my buckler in the “manner of a mirror” I hold it outwards and flat at the height of my face.
There is more support for turning the buckler to the face.
Qui voglio che tu butti il tuo piè dritto inanci, e con questo buttare voglio che tu butti il falso della spada in la copola del brocchiere e in quello battere tu voltarai la ditta copola inverso della tua faccia, & de lì tu butterai el tuo piè mancho uno gran passo dinanzi del dritto
The translation provided by Ilkka is
Here I want that you throw your right foot forward, and in this throwing I want that you throw the false [edge] of the sword in the cap of the buckler and in that beating you will turn the said cap towards your face, & from there you throw your left foot a great step in front of the right
This has given me a thought.
Normally I strike the front of the bucker, at the center of the cap. But if I turn the my buckler’s cap towards my face, not all the way around, just towards it a bit, then I it makes it much easier to strike the top of the cap from guardia di testa.
This could be used to close the high line between the sword and buckler and to lend strength to the parry by giving my weak something to rest upon. I’ll have to experiment with it further.