My go to fly, the all-time great Parachute Adams,works amazingly well whether on freestone rivers or spring creeks. Although I love tying and using them, I despair of ever getting the "classic" proportions! This one on a barbless #14 Partridge.
Depends on what I'm using for the post. If it's some artificial stuff like Tiemco Aero Dry, then I do what you do, i.e., even out by cutting. If it's something natural like calf-hair or tail, then I prefer stacking, the post just looks prettier, although I don't think the trout care one bit!