Don't think about ball position in relation to position of your feet. Think about ball position related to your front shoulder. We can judge ball position this way because our address position and impact positions are the same. (Traditional swingers or other swings can't do this.)
Variations in stance width and variation is spine tilt can change the ball position needed for a shot. For example if you look at some of the pictures of Mike in the Symple Swing manual you can easily judge the position of his front shoulder relative to the ball by looking at the lean of the shaft.
The lean of the shaft tells you where the ball is relative to your front shoulder. If the shaft is straight up (not leaning towards the target and not leaning away from the target) then the ball is directly opposite the front shoulder. In this position the ball would be struck at the bottom of the swing arc.
At impact your front shoulder is the axis of your swing arc. With the shaft straight up (again, not leaning towards the target and not leaning away from the target) the bottom of your arc would be opposite your front shoulder. That's a good position for a standard sized driver or maybe a 3 wood depending on the lie.
With fairway woods and long irons the ball should be addressed so there is a little lean forward of the shaft. That means the ball will be struck with a slightly descending blow. That's what we want with long irons and fairway woods.
With short irons there should be quite a bit of shaft lean. That means you are striking the ball with a very descending blow.
With the new big headed drivers and long tees you want to hit the ball slightly on the upswing. That means the shaft will actually be leaning back (away from the target) just a bit at address and impact.
Now realize that if someone had a really wide stance an a good bit of spine tilt that even though the shaft is leaning back just a bit it might appear to the casual observer that they were playing the ball back in their stance almost to the middle of their stance. It would appear that way because the wide stance and spine tilt (away from the target) move the position of the front shoulder back in the stance relative to the front foot.
BTW, when chipping there should be a good bit of shaft lean toward the target because your definitely want to contact your chips with a descending blow.
Even though I'm not giving your shaft lean in degrees I think you will find it very easy to find your correct ball position for any shot relative to your front shoulder with just a few minutes of experimentation.
You'll go crazy and never agree on any ball position if you try to judge ball position in relation to your feet. Judge your ball position relative to your front shoulder and you'll find a lot more success and consistency.
Judging ball position relative to your front shoulder does seem a little strange a first because it's a different way of doing things but I think you'll see the logic and precision of it very quickly. Good ball striking is all about where in the swing arc your strike the ball and the swing arc is controlled by your front shoulder.
One final note. Don't go nuts about ball position. On most shots it's not that critical. If you have a little to much shaft learn or a little less than you should the only difference your likely to notice is a difference in trajectory.
For example, I normally play my wedges back with a good bit of lean. However when I want to hit a very high shot to go over a tree for example, I would move the ball up so there would be no lean at address or maybe even in some special cases some lean away from the target. That would give me a much higher trajectory.
Having some shaft lean toward the target and having a descending blow is generally a good thing because it makes striking the ball a bit easier and more consistent. For example, moving the ball up for a high wedge shot can give you a nice high shot but it also increases the possibility of a bladed wedge winding up with a skulled shot across the green.
I hope that helps.