I will say that I have never used any Celestion or Jenson alnicos, nor any of the Webers based on them, but I have had a pair of Fane AXA12 alnicos for gotta be around 20 yrs now, and am up to four alnico EV SRO's.
The Fanes are 100 watts with iirc 35oz or 40 oz alnico magnets, and fiberglass voice coils. They're amazing speakers, and definitely the opposite of thin and fizzy. Milkshake thick midrange, with smooth rolled off treble and a round sweet bottom. To me they sound like a fatter and sweeter Greenback. They do that elastic and silky sweet vintage thing better than any other speaker I've tried. Awesome for blues, jazz, classic rock, even stuff like Sabbath they would be fine, but on the darker side. They have an awesome midrange grind to them when wound up and hit with gain or fuzz, but there is always this subtle velvety smoothness to the sound.
They would not be my first choice by themselves for metal, but blended with ceramic speakers that match well then that's another story. I had them in a 4x12 with two EVM12L's and they were awesome. The EV's provided the punch and clarity, the Fanes provided the fat midrange grind and sweetness.
Now they're paired with a couple Heritage G12H (55hz). It's a warm, fat, kinda vintage sounding cab that really does most everything I throw at it up to thrash to heavy stuff in like C to A standard.
The EV SRO alnico is the world's only perfect guitar speaker imho. From clean to crunch to heavy high gain distortion to thick fuzz, no matter what I'm playing I like it better through the SRO's. It's the only EV I've played that can go toe to toe with the best Celestions for chime and midrange kerrang, but hits harder than any of them on the lowend, and the highs are sweeter thanks to the alnico magnet.
Playing a neck pickup clean through them is relevatory, and playing a good heavy riff with distortion or fuzz puts a shit eating grin on my face every time. The only thing that sucks is they weigh a ton. Like 22lb or 23lb per speaker. So I currently have two with two Fane Medusa 30's in one cab, and two with two Celestion G12H-100's in another cab.