i was nervous about the holes too..and to be on the safe side, yeah..better to double grommet..but really, shouldn't they anticipate that when selling a cover? a lot of different shape pools out there. you can also i'm sure buy some plastic grommets that would still require a hole punch..i just slowly steadily (not too slow) crank up the cover onto the roller and it is fine..i go a bit slow anyway as i note the supplied suitcase latch looking type grommets with the little pegs and holes (if that's the type of attach kit you have) seem pretty lame and weak in the first place..but i've never had one come off or have torn my hole..even with my son who is a bull in a china shop, putting on the cover..once you get a few turns of cover around the roller, the stress is off them anyway before it gets to the real weight and cover resistance.