Photoshop Filter Render > Lighting - Couple Questions

Question

In regards to the Photoshop Filter > Render > Lighting I have a couple questions.

First: The easiest way I have found to light the photo is to create a new layer and choose Apply Image and make a merged layer of the image. This is fine but I have discovered that there are times I want to change something after that step. Is there a way to apply the filter to an empty layer as its own layer. Hence I can still edit everything in the document yet have lighting separate. So far I have not been able to figure a way to do this.

Second: The box that displays the settings is okay yet the preview is very small. Is there a way to enlarge or at least zoom in some to the preview so I can see what I am doing a bit better? Even nicer would be the ability to enlarge the preview to full screen like the Liquefy or other Filter commands do. If you cannot do that are their any Photoshop Extensions (preferably free) that someone can recommend that would help accomplish what I am looking for?

Answer 1

Wasn't getting much help here so I asked this in another forum and received this reply:

You could, I suppose, experiment with converting the image to use Smart Filters.
Look in the Filter menu near the top.  Not sure whether the other implications 
of doing that are acceptable to you.  I haven't done this much myself, but I do 
know that it works on an image layer, so it may not suit your needs - 
I understand what you want is something like Lighting Effects as 
an adjustment layer.

Regarding the dialog size, it appears to be a relatively old filter, and 
there's no way to change the dialog or preview size for it, nor any zoom 
capabilities.  Changing a filter to use an updated interface - e.g., one with 
a resizeable dialog and full zoom capability like Lens Correction - is not a 
trivial task (I know this because I've implemented such a framework for my
own plug-ins).

-Noel