As title, does it make any difference? Should they be fully in, out, or half way? What is the reason for your answers?
As long as the port from the reservoir to the master cylinder isn't closed, it should make no difference. If the lever pivot is seized, or unable to move for some reason, and you try to wind the lever out (i.e. as though you have bigger hands), it's possible it could move the piston instead and close the port. It shouldn't, but winding them in if you are having trouble bleeding would eliminate a possible source of trouble.
Hope tell you to wind everything out before bleeding, so I guess it's the same for all bite point and reach adjusters, it gives you more throw to pump more fluid through, probably.
Actual lever position wont make any difference on a shimano bleed , reach adjuster doesnt move the fluid pistion inside
Although if you have the free stroke adjuster ( the small 2 pronged bolt on the front for SLX M7000 models and later ) then unscrew this all the way out prior to a bleed , it will allow more fluid in
