It's slightly above where those strings you found were. Should look something like this for each disposition (unless determined via import).
"Topics": [{
"TopicID": "e79eabe7-8d68-4cf4-9a07-3e84b154d6ec",
"Axis": "Negative",
"WeightID": "d8cd9f8e-5be6-4036-a8cb-48afbd7edc54",
"Conditional": {
"Operator": 0,
"Components": []
}
},
The above is for Aloth being anti-tradition.
TopicID is the disposition 'tradition', the axis is negative for anti and the weightID has something to do with strong/weak (i'm assuming dispositions are flagged as major and minor effectively which would impact the reputation loss and gains maybe, and they are also linked to the line of dialogue that fires when the companion reacts) Theoretically, you should be able to just change the TopicID to an existing ID for a different disposition.