I used just plane modeling cement. I am hesitant to make anything brittle as I my track record is not very good when handling things that are far-gee-lay (must be italian). I tried scribing, and in person you can see a small gap, I will go back over it some more and then leave it alone.
And now a question about painting....
In a past post (searched on my phone so I do not have a url) it was noted that new subs do not have the hull red but rather its a kind of a grey/black instead. Tracy, you posted links to some of your builds of USS Skipjack and USS Los Angeles. On the Skipjack you used model master's "aircraft interior black" between the hull red and flat black top. The Los Angeles was just flat black with the red.
Would it be correct to use the aircraft interior black for below the waterline on this model, and flat black for above?