Before completely sealing in the servo lead, dental floss is tied at the plug and taped down. Later, after the wing is covered, I can reach in with tweezers and use the floss to pull the servo plug out. (Well, it's a servo extension.) This keeps the plug and lead out of the way while sanding & covering.
The best way to retrieve the servo plug after it is entombed when the top sheeting is glued down.