I don’t think it ought to matter, if the holes are designed right. In simplistic terms, the “vertical” angle will change throughout the year, but the “horizontal” angle won’t. So long as those numeral holes aren’t round holes, but are more like slots, then this should work even with a changing vertical angle. Much like a sundial’s shadow will still hit the hour lines, even though the shadow itself becomes longer and shorter.
More precisely, the hour lines aren’t straight lines but make an analemma, but I don’t know whether this is significant enough in a small sundial that it needs to be factored in to the shape of the holes, or if the holes can just be a little bigger to allow for some wiggle room.
If it’s precise enough, it could actually be more accurate than a regular sundial, because if the pin holes can account for the analemma then that takes care of the Equation of time inaccuracy. But thinking about it, maybe we can’t account for that just in the hole’s shape, and that needs to involve marking the locations of the numbers on the base.
Without fancy adjustment, it’s still fairly accurate throughout the year, just as a regular sun dial is.
