Same here.Yes.
Very slightly.
If you chamfer before at least neck-sizing, you'll likely be chamfering an out-of-round case mouth. I don't think it matters in relation to tumbling. Also, depending on the tool used you should deburr after sizing/trimming/chamfering. Most of the deburring tools depend on consistent case length and a round case mouth.Does it matter when you chamfer/debur? Like before/after sizing ... before/after tumbling ... ?