Actually I just found out the tube is to put between the wing sheeting and the ribs for the wing bolt guide.

Im using 3/4oz cloth on the fuse and and wing.
Im mixing up zpoxy finishing resin with a bit of alcohol and painting it on the ailerons, elevators and rudder.
Then im mixing primer with microbaloons and coating them and lightly sanding.....I will do that a few times then paint them.