Hi Hystoryan,
I think highly of Gardner and you can see some of my comments about them at the end of this post and in the Boston list here.
The 9" latex would have no weak links if it was latex from top to bottom.
I don’t know the specifics of the materials in the pocket coil you are considering and if you can post the details here (post #4 here has the information you would need) I’d be happy to make some comments about it although based on my knowledge of Gardner it’s unlikely that it would have any obvious weak links either.
The information you need doesn’t need to be in writing as long as you know it.
Phoenix