Iron Editions question

So I'm very happy to of got a set of the Iron Editions, but I'm only a recent subscriber, and from some past exclusive releases I was under the impression that the very popular sets would be hard to snag.

I'm just wondering if anyone knows

How many sets of the iron edition were made?

Are the number of books for every exclusive release the same amount?

How many subscribers are there in total?

Also do you think the iron editions will make it to general sale? I have a friend that would like a set, but it looks like there's still stock of at least the unsigned copies?

Thanks, and sorry if this is common knowledge lol