Over the years I have prepared several such Halliburton cases for the photographers I assisted in Hollywood.
Here are my tips:
A very sharp knife, used with very short strokes, sharpened with a rough ďtoothĒ is best. An ideal candidate would be a Japanese laminated kitchen knife, such as this one from Lee Valley:
Lay out the equipment on poster board and cut out with an exacto knife. Then trace the posterboard onto the foam with a Sharpie.
The purpose of the layers of foam is to be able to center the equipment from case top to case bottom. The bottom layer is obviously never cut. Arrange the other layers to suit the equipment: thicker equipment requires the hole to be cut in more than one layer.
Arrange the equipment with regard to weight, or the case will be unbalanced.
Donít place the equipment too close together or the foam will tear with use. This is where gluing the layers can add strength. But donít glue multiple layers where you intend to cut through only one.
Some glue will dissolve some foam. I seem to recall having success with water-based non-flammable contact adhesive.
Another trick is to glue a layer of leather from Tandy on top of the foam, before cutting. Dyed black, it can be both strong and look quite elegant.
An alternative source for this sort of foam is:
Be sure to read the bit about types of foam, so you order the correct material.
I am about an hour north of you via route 91 in Springfield. If you have a problem, e-mail me for directions and Iíll demonstrate my technique. If you get one of these knives, I can show you how to resharpen it on a Japanese water stone, after you dull it on the foam (out of the box it is like a straight razor).