I would prefer an offertory song, but accept that it is optional.
Some extracts from the 2002 General Instruction of the Roman Missal (GIRM) approved for the USA, which can be accessed from
romanrite.com/girm.html on this:
“74. The procession bringing the gifts is accompanied by the Offertory chant (cf. above, no. 37b), which continues at least until the gifts have been placed on the altar. The norms on the manner of singing are the same as for the Entrance chant (cf. above, no. 48). Singing may always accompany the rite at the offertory, even when there is no procession with the gifts.”
“139. When the Prayer of the Faithful is completed, all sit, and the Offertory chant begins (cf. above, no. 74).”
“142. … If, however, there is no Offertory chant and the organ is not played, in the presentation of the bread and wine the priest may say the formulas of blessing aloud, to which the people make the acclamation,
Benedictus Deus in saecula (Blessed be God for ever).”
“
Silence
45. Sacred silence also, as part of the celebration, is to be observed at the designated times.
[footnote 54. Cf. Second Vatican Ecumenical Council, Constitution on the Sacred Liturgy, Sacrosanctum Concilium, no. 30; Sacred Congregation of Rites, Instruction Musicam sacram, On music in the Liturgy, 5 March 1967, no. 17: AAS 59 (1967), p. 305. ]
Its purpose, however, depends on the time it occurs in each part of the celebration. Thus within the Act of Penitence and again after the invitation to pray, all recollect themselves; but at the conclusion of a reading or the homily, all meditate briefly on what they have heard; then after Communion, they praise and pray to God in their hearts. Even before the celebration itself, it is commendable that silence to be observed in the church, in the sacristy, in the vesting room, and in adjacent areas, so that all may dispose themselves to carry out the sacred action in a devout and fitting manner.”
“The Importance of Singing
39. The Christian faithful who gather together as one to await the Lord’s coming are instructed by the Apostle Paul to sing together psalms, hymns, and spiritual songs (cf. Col 3:16). Singing is the sign of the heart’s joy (cf. Acts 2:46). Thus Saint Augustine says rightly, “Singing is for one who loves.” [footntoe 48: Saint Augustine of Hippo, Sermo 336, 1: Patrologiae cursus completus: Series latina, J. P. Migne, editor, Paris, 1844-1855, 38, 1472] There is also the ancient proverb: “One who sings well prays twice.”
40. Great importance should therefore be attached to the use of singing in the celebration of the Mass, with due consideration for the culture of the people and abilities of each liturgical assembly. Although it is not always necessary (e.g., in weekday Masses) to sing all the texts that are of themselves meant to be sung, every care should be taken that singing by the ministers and the people is not absent in celebrations that occur on Sundays and on holy days of obligation.”
In the 2007 Encyclical Sacramentum Caritatis, Benedict XVI wrote:
“***The presentation of the gifts ***
47. The Synod Fathers also drew attention to the presentation of the gifts. This is not to be viewed simply as a kind of “interval” between the liturgy of the word and the liturgy of the Eucharist. To do so would tend to weaken, at the least, the sense of a single rite made up of two interrelated parts. This humble and simple gesture is actually very significant: in the bread and wine that we bring to the altar, all creation is taken up by Christ the Redeemer to be transformed and presented to the Father. (footnoe 144: Cf. Propositio 20.) In this way we also bring to the altar all the pain and suffering of the world, in the certainty that everything has value in God’s eyes. The authentic meaning of this gesture can be clearly expressed without the need for undue emphasis or complexity. It enables us to appreciate how God invites man to participate in bringing to fulfilment his handiwork, and in so doing, gives human labour its authentic meaning, since, through the celebration of the Eucharist, it is united to the redemptive sacrifice of Christ.”
I think silence would tend to head in the direction of an interval. Singing would tend to focus on the importance of the Presentation of the Gifts.