Holes are actually not important - the larger, within reason, the better. Don't forget, I put my potted orchid plants in these glazed ceramic pots. If you look real close, you will see what kind of pot I am using - you can see black (plastic) or clay colors through the holes/slots of the ceramic pots. Since I am using these ceramic pots to double-pot my plants, there is no orchid mix to worry about.
Size matters whether you glaze them or not. Unglazed, they could better be used as "growing" pots. They would be able to "breath". Glazed pots are simply something I use for aesthetic purposes and to stabilize the plastic and clay pots. The problem with using the nice, expensive glazed pots for growing is that the orchid plants will send roots out through all the holes/slots. It can be difficult to remove the plant when re-potting. Your large glazed pots could hold a 5-6 inch "growing" plastic or clay pot. The smaller the glazed pot, the smaller the "growing" pot would be to fit within it. So, if I were a potter (I can do it but it kills my back), I would have sizes ranging from 4" up to 12", round, square, and even rectangular. The rectangular could be used to grow a nice, large Phal. (which doesn't need repotting too often) or two small orchid plant sitting side-by-side. I hope this helps some. I can't wait for you to experiment some and post the pics of what you have done. Only your imagination limits your pot creations.
I will send you some more pics of much larger and very different orchid pots I have and tell you the size of each.
P. S. You don't live close to Mississippi by any chance? Ken
