I think the choice on what replacement speakers is totally dependent on what sound you are looking for. When restoring a vintage amp most people want to use speakers that capture the vintage sound associated with that amp. I would think that Eminence 12s would sound
"correct" in your vintage Model T. Sunn did use JBL speakers as well, so if you like the "clear edge" West Coast sound, then either JBL D120s or K120s...or maybe Weber California Series would be a good choice.
My only experience with Webers is in restoring a '62 brown vintage Fender. His P10Qs sound wonderful...for a really great clear, vintage sound.