The Garrison Membership Liaison (GML) is the person whose job it is to check that the costume you have built matches the requirements from the CRL in order to join.

So it is recommended that you contact the Icelandic GML for assistance before you start your costume.
They can help make sure your costume is up to the necessary standards, and can give advice about your costume, such as where to get parts, what things to adjust before applying, etc. etc.