A Full or 3/4 insole should do the trick but not less than that.
Support
Look for arch support for your specific arch type; most insoles indicate whether they offer low, high, or neutral arch support. For Overpronation, the arch type is usually low, so seek a low arch support insole.
Cushioning
A still insole with ample cushioning.
Cover
Smooth and moisture-wicking top cover.
Design
Contoured design or a deeper heel cup for stability.
Pronation
Size
A Full or 3/4 insole should do the trick but not less than that.
Support
Look for arch support for your specific arch type; most insoles indicate whether they offer low, high, or neutral arch support. For Overpronation, the arch type is usually low, so seek a low arch support insole.
Cushioning
A still insole with ample cushioning.
Cover
Smooth and moisture-wicking top cover.
Design
Contoured design or a deeper heel cup for stability.
Pronation
Insole for Pronation