Between hull 160 and hull 190 you need the interface.
As I wrote in "Instructions":
The interfaces are supposed to put them fifty-fifty in the gap of each hull part. In this way the the hull parts are aligned and easy to glue.
Before gluing you should mask the edges of the hulls with tape to keep them clean from glue.
In your case you don't need to use the full length of the interface.
I use 2 component epoxy glue because you don't have to hurry when you are gluing.