Anyway, not knowing what caused the rectifier to fail, I didn't want to risk blowing my backup GZ37 or GZ33 tubes so I plugged in the original Weber WZ68, replaced the fuse, crossed my fingers and powered up the amp. All is fine. Back to normal.
Here's the interesting part: I swear the amp now has more balls in the low end! The bass sounds deeper and tighter. Furthermore, I have not noticed any change or sacrifice in mid or high frequencies. I'm going to run the amp with the Weber for a few weeks and then try another GZ37 to see if I can hear a difference and confirm what I think i heard.
I don't want to start a solid state vs tube rectification argument, just figured many of you would be interested in the experience.