Hi Ralph, I am tempted to give the 60w bulb method a try. As I said I currently view near a window out of direct sunlight and while the tones look good there when moved away from the window they loose their sparkle and look to dark. I don't think many people who are likely to buy my work are in the position of installing a lighting system to view the print under ideal conditions, they will most likely just be hung on a wall where there is space and they look OK.
As for galleries, if a gallery is trying to sell works then the lighting is usually good (it is in their interest to make the work look as good as possible) but I find the lighting in many public galleries to be terrible. These places are run by curators and, as with the dry mounting verses archival mounting argument, they appear to think that any photon falling on the work will instantaneously fade the image into non-existence. I can understand being cautious for major historical works that may have been created when the properties of the materials were not fully understood but surely a well produced photograph created on quality modern materials should be able to stand a reasonable amount of UV filtered illumination without degradation. A new gallery near me that was recently completed at a cost of millions of pounds of public money installed a lighting system that was obviously sold to them as being state of the art archival lighting that consisted of LED spot lights. The spots produce a small circle, approx 60cm, of dim, what can only be described as, grey light and then fall off into almost darkness. When illuminating large works there were a few pools of dim light and the rest could hardly be seen.