The rectangular recess pockets are for
mounting servos. The servo arm should
pass through the corresponding slots.
This arrangement is to provide better
linkage geometry than previous designs.
Notches will help line up parts. Most
builders have a glue preference. Many
glues will work well for this.
Horizontal nose, midsection, wing panels
and elevator assemblies can all be glued
up with parts laying flat on build table.
Only thing to watch for is to not fill carbon
slots with glue.