Speaker combination

Hello,
I have recently build 1x12 guitar cabinet for my home practise. And it turned out pretty nice. I like it very much. I like the bite, lowend and overall sound. I used Celestion V30 8ohm.
So as a next step I decided to make something for my main rig. I'm playing Diezel VH4 stereo head through Blackstar Artisan 4x12A stereo cabinet with V30s.
I'm thinking about making two 2x12 cabs. But I'm really intrigued by idea of using Celestion 15" Fullback speaker in botom position of each cab.
I know that the most important parameter in combinig speakers is dB sensitivity. I have the idea of pairing 15 fullback with V30 or Alnico Cream.
I've found the only manufacturer making these kind of cabs is Friedman 412/15 cabinet. They are using 15 fullback in combination with G12H30.

Do any of you have tried this combination? Or any other combination with 15'' Fullback?
What do you think of idea of having two different combos. For example Fullback with V30 in one cab and Fullback with lets say G12H-75 Creamback in the other.

Thank you.

I would recommend building two cabs each with a 12" and a 15".

I have a Randall cab similar to the diezel with two 12's and a single 15". Massive tone.

Or build two mesa theile cabs with an eminence delta pro a or an EVM12L.

they are likely the best cabs I have ever played.

Hello, thank you for your response.
By now I'm convinced to make two cabs with one 12" and one 15" speaker. I thnik it will be awesome. Or maybe not, but I'd like to experiment.
I already did some plans. It will be 33,5 x 21,6 x 15 inches. Kinda oversized, but I hope will deliver a nice lowend.
Here is a visualisation how it will look comaring side to side with my actual Blackstar cab. Which itself is oversized a bit.

The eminence legends are pretty good for cheap imo. I have not tried a 15" mesa speaker.

I can almost promise that you will love having the 12" and 15" combination.

If you want to break the bank, i once played (not owned) an EV 15. It was an earthquake.