The ring height is only going to be a problem if it's so high the strings catch on it. I've got guitars where the pickup rings are quite high and so the pickups are flush with the rings. They look and play OK (and you are normally only going to see this yourself).

You don't want to raise the action just because your pickup rings are well-endowed in the vertical stakes, so if they are too high, you may have to spend some time sanding them down. Hopefully the bottoms are already curved and the curves fit the curve of the guitar top. Which means you may have to put some sandpaper on the top of the guitar and sand them down on that, so that the curve still matches that of the guitar.