I have the forks, but not the tooth bar. They do not have to be used together. You'll notice on the two ends of the toothbar the smaller tooth is left off - so you can leave the tooth bar on and put your forks on at these locations. Without the tooth bar you can slide and use the forks anywhere along the bucket.
Harry mentioned in another thread that he will customize the tooth bar if you like. That is, you can leave any or all of the smaller teeth out to retain more flexibility on where the forks can locate along the bucket without removing the tooth bar.
I don't know what the forks are rated for but I can tell you my experience. I've used them for loading logs onto a trailer. As I kept working and adding more logs on the forks with each lift, I reached the point where I could overload the amount my
BX24 loader would lift and the forks were still fine, never even bowed or anything that I could tell. I'd have to remove a log so the loader could lift the load. Those forks are pretty tough.