The tops of your arms should just rest lightly on your chest. So as you bend over more with a short iron your hans will be about 5" from your thighs. Moveing farther away as you stand straighter up to the driver. Then the gap will be more say 9/10". This is only aproximate, as your size and built will effect it as well.
Filmed myself and my brother at range a few weeks ago, I knew i don't stand upright enough at address but was shocked to see how bet over and stretching for the ball i was, compared stance against my brothers position and found i stood about a foot further away from the ball. Been told many times about my stance but didn't think it was as bad, need to get used to new stance and lose a bit of weight to allow arms to drop down more vertical. Also feeling the benefits as no lower back pain after a range session.