Standard for practice as preached by any coaching certification course I've ever done (and used by extensively by all Olympic archers) is a "Blank Bail".
There is some talk about it here, in this case the strong form of it is to stand close enough to the bail you know you can not miss, *close your eyes*, and work on form.
Can't get much darker than that. I suppose one could go down into a cave and close their eyes - but it wouldn't make mush difference
Yes, the more distractions you remove from concentrating on form the better your form will become. Your form will improve even better if you drop the whole grouping and trying to hit the target thing too - that is just a distraction.
Of course, you also have to know how to translate that form into hitting the target (well, sorta, some forms of Japanese Kyudo use the act of shooting as a type of meditation so I guess there are some people out there who just like the feel of concentrating on form and nothing else). But that is a whole other process (start close, large target so no fear of missing ans shoot until it all becomes second nature and slowly work back/smaller targets keeping that feeling of letting things happen - in a somewhat short time you should find you can keep that form/concentration good even at long yardages).
My guess is this type of thing is how people learned that blank bailing is beneficial in the first place.