I would imagine that bolting the cones together would allow no air gap for the sound waves to cancel each other and be louder. I dont subscribe to lengthy break in theory. 10 or 20 hours gets the suspension loosened. I consider anything past that as "getting yourself used to the speaker" and not breaking in the speaker itself.

Lacking a safe to put them in and not wanting to demount too
often, I'll put the speaker/open baffle board assemblies in a box
with some fiberfill, turn up the juice and leave.