I never had any but it's know to overgrow the scion.

Most of my trees are grafted on FD (both container trees and in ground trees). As pip wrote, FD does over grow the scion, but that has never been a problem. FD is my rootstock of choice. My inground trees grow to approximately only 11 feet, thereby it remains easy to harvest the fruit. FD also gives my trees a few additional degrees of frost protection. -S-

I'd like to find some FD seeds to do some grafting on my own. Know where to find the seeds?

Yes i know where. Check out ebay i just checked and found them.

Hard to trust ebay seeds. If you look around ebay, there are a lot of seeds for sale to plants that don't even exist. I'm afraid of buying FD seeds and end up getting store bought lemon seeds or something.

Give it a shot hell, why not? I bought seeds several times from ebay never had issues. And well if you get something you didnt pay for you can open a dispute with ebay and you will be refunded . I dont think sellers would sell something else from whats listed and hurt their reputation

I have several trees on FD root stock with no problem. I also have seeds.