Subwoofers for Stacked Quad ESL 57's

I would greatly appreciate your timely opinions based on direct experience. Thank you
I experimented years ago using a single pair of the old esl, decca ribbons, and could not get a conventional woofer to blend well. There is a possibility that you could use a planar type woofer- years ago, HP had Tympani bass panels with Quads, I think. One designer i talked to more recently said he modified a Quad 63 to act as a bass driver to augment a pair of 63's. One of my long range plans is to restore my old pair ( I have both the 57 and the 63 Crosby mod) buy a second pair of 57's and do a vintage stacked Quad system. So, I'm interested in what others recommend here.
A horn loaded woofer might be interesting....
Do you have a frame for the Quads?
I have old literature on stacking Quads somewhere, along with diagrams.
Cool project.
Thanks very much. I do have the frames. I have heard that a transmission line sub is the way to go for the most seemless integration and quickness to keep up with the stacked quads, but I am very open to fellow Audiogoners opinions. I would be interested in the diagrams because I am considering building new stand as well.
Rmarcus - I sent you a PM, please let me know if you got it.
I haven't received anything. Can you I trouble you to resend it?
I think if I include an email in the message they block it. That's why you didn't receive it. My media website is flyingreptilemediagroup if you go there you can email me from there. What a pain. It is not like I am trying to deprive the Gon of a commission on some old drawings.
I have a pair of HQD-like stands for stacking Quads with space for the tweeter in between that are not in use. I purchased them from someone years ago but never got around to setting them up.
please provide a way that I can contact you directly as I am very interested in learning more about them.

Thanks in advance

I'd like to get additional information on your stands. What is the best way for us to connect? Please advise asap. Thanks much.
Subwoofers for Stacked Quad ESL 57's? See:

These really are fast enough and transparent enough to integrate seamlessly.
Thanks very much. Do you use them with esl 57's?