Reversing a lens generally gives you a very small working distance. That’s normal: the subject often ends up only a short distance in front of the reversed lens, which makes lighting difficult.

In practice, if your goal is both high magnification and more working distance, the better approach is usually to use longer focal lengths with modest extension rather than relying on a reversed-lens setup.

So for your question: a reversed lens setup is not the best way to preserve working distance. If you want more room between the front of the lens and the subject, move toward longer focal lengths on the taking lens and use short extension tubes as needed.

For the lighting problem, common solutions are:

• use a tripod and longer exposure for still subjects
• use a ring flash or ring light

Your DX body doesn’t change the optical working distance; it mainly changes framing and field of view.