What kind of targets, what position?
If tiny targets and/or benchrest, you would benefit from more magnification.
If prone or field position with sling or bipod on bullseyes or humanoids, you are ok.
I started in F class (bipod) with a 3.5-10, replaced on warranty with a 4-12, always at maximum power.
But I upgraded to a 8.5-25 variable and worked my way up the scale to full power except when mirage was bad.
If I got a fixed power for that, it would be a 20X.