Looks great! Fits with the games art style and doesn't look cartoonishly disproportionate or generally absurd. Something I have noticed that's been quite irritating though is that when using an addon that removes the borders of the SDT application, such as xlstaticbgload by Sby, for some odd reason a second par of nipples can be seen hovering offscreen behind where the border typically would be. They're still attatched to the model as they move with the character but they're just floating off to the side. I was really hoping that this could be fixed in a patch at some point.
Regarding the issue with the arm placement:
The cupping/holding breasts positions are a feature of animtools.
I'm not sure how this is implemented. Possibly the hands are placed relative to the breast mod's origin point so that the hand matches the position of the vanilla breast artwork? This of course won't fit the modified natural breast's shapes.
I don't think that I can do to fix this in the scope of the natural breasts mod alone.
Having an (invisible) symbol which designates the hand placement point, which is then used by animtools might be a strategy for adding compatibility for the hand positions.