CJ
The bike looks very nice.
as a thought, now that I see how you did the couplers, can you consider a slight mod to the design. I am not sure what diameter the tubes are where coupled, but it may be a worth considering a titanium outer skin over those tubes.
On the internet is a place called titanium Joes. He stock surplus and small quantity titanium tubing and sheet. Possible you could get some thin walled tubing and line the bearing surface of tube.
There will minimize any fretting type wear with carbon on carbon, and will protect the tube ends while dis-assembled.
Obviously I my be entirely wrong because you have mentioned something about what sounds like a core in part of the structure.
Just something maybe worth considering.
Looks very nice though.
PK