Restock:
I bought the 6sf5gt's from tubemandotcom. I believe they were $7.00 per tube. Just make sure to tell them you want the gt's. But they are good people to deal with.
I have a pair of Cardersound Tybones with EnABled Fostex 126e drivers. They are not quite as cosmetically fancy as yours, but they are similar...really Big double mouth, backloaded horns. I also use The Cube Bass Augmentor built by Ed Schilling of The Hornshoppe. It is a beautifully designed sub (even though Ed prefers "augmentor"). Integrates perfectly with the main speakers.
The FiX gives the sound an indescribable -I'll use "ethereal"- quality. I can't wait to hook up the Y pre and phono. I should have them by the end of August, after a 5 1/2 month wait.
Aaah, there's nothing quite so good for the soul as a bit of deferred gratification.