Depends how big of a label you want. There is no answer to this question. I suggest you find a label you like and measure it.
I use 2.5 x 3 and that is probably on the small side.
Most definitely Reggie. I like hearing/reading about how other professions do there job. Always like to be learning new stuff.
Names, no names, doesn't matter to me. Pretty sure it is all public record and readily available?