How Large is Hole Diameter for Thru-Hull ?

[erict]

Still prepping to haul the boat and replace seacocks. Current seacocks are hard to measure accurately due to tight space. My best measurement is 1.30" which might mean 1.25" or possibly some strange metric size that is slightly larger.

How much larger can/should the hole be compared to the thru-hull fitting?

If current hole is 1.35" is that too big for a 1.25" thru-hull? If so, then I'll plan to enlarge the holes to 1.5" but I'd prefer not to have to do this.