You seem to be hung up on cone assembly mass.
The mass of the cone assembly is only one of a dozen or more factors considered then designing a driver for a particular application.
Those 10 inch not 12 inch 2261H drivers used in pairs in jbls VTX V 20 are useful down to 80 hertz and -10 dB at 60 hertz in that design but of course you knew that.
https://jblpro.com/en-US/site_elements/v20-spec-sheet
The application notes for LF reinforcement are here.
https://jblpro.com/en-US/site_elemen...es-vtx-v20-s25
If you are interested in the 2261H buy a pair and evaluate them after determining a suitable design from the TL parameters. That is a good place to start. Only you can assess the suitability of the 2261H for your project.
As Robert pointed out in an earlier post you seem more interested in
going down your own road (rabbit hole) than listening to recommendations from experienced members here.
Using these forums to sound out your strategy is at best risky as only you can make the relevant decisions, bite the bullet and then do the real work which can take quite a while.
It will go but as they say it won’t lick itself. You will spent quite a while getting it to sound listenable.
No one is suggesting your project will not be an interesting experiment but without clear viable design goals and a disciplined approach to implementation a lot could go wrong and it does. I recommend you read Drew’s Clues in the Library which carefully describes a similar system to what you might have in mind by a highly experienced Jbl employee.
Such large format systems require scale up.
This means everything including the venue and the listener distance like at least 5 -10 metres and preferably 10-15 metres. The acoustic power inside a solid structure without due attention to absorption or large bass traps can reach a point where the structure rings continuously according the reverberation time at specific frequencies. Bowel evacuation follows.
If that is what you have in mind JBL manufactures turn key solutions for clubs using the drivers you have mentioned. Would it make sense to consider a proven JBL engineered pro solution than spend time evaluating a myriad of options? Sometimes it pays to listen.
I wish you all the best with your project.