There's no control on that per field - the closeness of the match just contributes to the overall match score.
Suppose you have two fields, F1 and F2 and you do fuzzy match on F2.
F1: 'Val1' F2: 'Val2'
F1: 'Val1' F2: 'Val3'
would score, hopefully, 87.5% overall.
F1 is a perfect match worth 50% of the overall score. F2 is a fuzzy match which is, in isolation 75% - apply that to the field weighting for F2 which is 50% and you get 37.5% for F2. The overall score for the match is 87.5%.
In other words, fuzzy match just gives a 'score' for a field,
If the combined score is good enough for the partial match (across all fields) then it becomes a partial match
That overall score needs to be above the partial match threshold for the match to be used.