That is a nice looking plane. At this point I set the plane outside in direct sunlight. Let it set a half hour or more. Iron any areas that wrinkle until they are smooth again. I don't use a heat gun now because it covers too large of an area. Set the plane in the sun again and repeat until there are no more wrinkles. Your plane should stay tight for a long time and won't look like a prune it's first day on the flight line.