I decided to try the Celestion Eight 15 in my Bronco. It was the most inexpensive available in Canada that I could find. The break in wasn't too long, and it gets sweeter every day. It exceeds the Weber Sig 8 alnico in my 1968 Vibro Champ.
The Bronco has several mods that truly shine with the Celestion. It takes the drive better and is more musical when driven to crunch. L&M had the best price in Canada and no delivery charges.