When I want high build, fast cure and excellent feathering I use Evercoat Glazing Putty, two part polester type and stinks like you would not believe. For solvent putties I like Squadron white as a base on styrene because it has the best "grab", Model Master/Bondo red on resin as a base coat because it "grabs" well, Acryl blue for an intermediate layer because it feathers decently, sands easily and is not white or red...you do know changing colors each layer helps spot defects. For top coats I use either Tamiya silver/grey or Spies-Hecker Permacrom 7715. The Permacron is the best feathering putty of the solvent types, dries much faster than the others and will take a polish.