You could paint the underlying paper grey before attaching it. So you could make the gap virtually invisible. Scribbling with a pencil should do the trick, just ever so slightly till the tone matches the base colour of the saucer.
Small update. Got distracted last Night as I found out GOG we offering Total Annihilation for free for 48 hours - downloaded it a played against my brother online - took me back 20 odd years!
I built the ENT-C in 2008! Clever Santoro sent me the file and i did a rework of the unfolded sheets! Unfortunately he never uploaded the new file! Also i started a rework on the Yamaguchi, but i never finished it!
BTW that is what i call "Star Trek: Generations" (old pictures, without the NX01, and all in same scale)