I would ask my county extension agent, in the phone book under county government, what rootstock does best in your area and where you can get it. Of course, they may ask what you want the rootstock to contribute tothe final tree. Your taxes pay their salary and questions like this is why they are working.
Specific rootstocks give certain qualities to the final tree. Some are more resistant to certain diseases, some control final tree size, some handle hot or cold weather better, some may do better in wet or dry conditions. Just like you pick a tomato variety for qualities you want, you pick a rootstock for your conditions. If you just graft an apple tree to any old apple tree rotostock there is no telling what you will get.
Odds are if you talk to your county extension agent, they can hook you up with an expert on grow in apples in your state, probably someone at your state land grant university. That's who they will probably go to so they can answer your rootstock question anyway. You might ask if you can talk to them directly. I don't know if the odds of getting an edible apple growing from seeds are as bad as given in the linked article, but I know they are pretty bad. And I was aware commercial growers often use crabapple for cross-pollination, not other commercial apple types. Not all, but some. That's a big reason I planted crabapples around my apple trees. I don't have a good pollinator for my early apple. I don't think I would purchase rootstock to graft apple trees grown from seed on until that apple tree had produced apples that I thought were acceptable. If you have the time, space and inclination you can certainly try growing them from seeds, but I think if you spoke to someone who was very knowledgeable about it, you may change your mind on your approach. It is a long term investment of space and especially your time. This is coming from someone who grows cross-pollinated winter squash just to see what I get.
http://gardenspace.newarchaeology.com/apples_from_seed.php
Good luck!!!
With all this said, may I ask where you bought the apple seeds from? After typing all this I noticed you said you
bought the seeds. There may be something going on here other than total absolute random selection????