Painting wing tips and cover plates

I spent a large part of today preparing parts for painting, then painting them. Most of it was straight forward, except for the wingtips. I had degreased them well. First I primed them, then used a body filler. This was problematic and took a lot of sanding. Even then, I didn't get a great result. I've put a top coat on, but I may need to redo some areas.