Embedded data array verses embedded data map

I have a choice of loading data in two ways. There is always a header portion and data portion of each document. The first way with the data portion being nested objects, and second with the data portion being an array of objects. Could someone please advise me if there are advantages or disadvantages to either way considering ease of querying and performance? There will potentially be hundreds of elements in the data section and they will be ordered by the “fl” field. There will be millions of these documents. Here are the two options…
first data as nested objects…
{
“id”: “DD::V01::SAL1L2::GFS::G2/NHX::HGT::GFS::P1000::2018010100”,
“type”: “DataDocument”,
“dataType”: “V01_type1”,
“subset”: “mv”,
“dataFile_id”: “DF_id”,
“datasource_id”: “DS_id”,
“version”: “V01”,
“model”: “ford”,
“geoLocation_id”: “123”,
“data”: {
“12”: {
“fl”: “12”,
“total”: “3600.”,
“fs”: “0.885379982E+01”,
“o1”: “0.815554852E+01”,
“m1”: “0.473878674E+04”,
“ff”: “0.472373419E+04”,
“fa”: “0.477779363E+04”,
“oo1”: null
},
“18”: {
“fl”: “18”,
“total”: “3600.”,
“f5”: “0.920275537E+01”,
“o1”: “0.815554852E+01”,
“m1”: “0.476554197E+04”,
“ff”: “0.478906976E+04”,
“fa”: “0.477779363E+04”,
“oo1”: null
},
“24”: {
“fl”: “24”,
“total”: “3600.”,
“f5”: “0.924388284E+01”,
“o1”: “0.815554852E+01”,
“m1”: “0.477780374E+04”,
“ff”: “0.482988206E+04”,
“fa”: “0.477779363E+04”,
“oo1”: null
},
“30”: {
“fl”: “30”,
“total”: “3600.”,
“f5”: “0.969193197E+01”,
“o1”: “0.815554852E+01”,
“m1”: “0.479433046E+04”,
“ff”: “0.488857497E+04”,
“fa”: “0.477779363E+04”,
“oo1”: null
}
}
}

and Second with data as an array…
{
“id”: “DD::V01::SAL1L2::GFS::G2/NHX::HGT::GFS::P1000::2018010100”,
“type”: “DataDocument”,
“dataType”: “V01_type1”,
“subset”: “mv”,
“dataFile_id”: “DF_id”,
“datasource_id”: “DS_id”,
“version”: “V01”,
“model”: “ford”,
“geoLocation_id”: “123”,
“data”: [
{
“fl”: “12”,
“total”: “3600.”,
“fs”: “0.885379982E+01”,
“o1”: “0.815554852E+01”,
“m1”: “0.473878674E+04”,
“ff”: “0.472373419E+04”,
“fa”: “0.477779363E+04”,
“oo1”: null
},
{
“fl”: “18”,
“total”: “3600.”,
“f5”: “0.920275537E+01”,
“o1”: “0.815554852E+01”,
“m1”: “0.476554197E+04”,
“ff”: “0.478906976E+04”,
“fa”: “0.477779363E+04”,
“oo1”: null
},
{
“fl”: “24”,
“total”: “3600.”,
“f5”: “0.924388284E+01”,
“o1”: “0.815554852E+01”,
“m1”: “0.477780374E+04”,
“ff”: “0.482988206E+04”,
“fa”: “0.477779363E+04”,
“oo1”: null
},
{
“fl”: “30”,
“total”: “3600.”,
“f5”: “0.969193197E+01”,
“o1”: “0.815554852E+01”,
“m1”: “0.479433046E+04”,
“ff”: “0.488857497E+04”,
“fa”: “0.477779363E+04”,
“oo1”: null
}
]
}