Stu, my understanding is that the main difference between spindle gouges and detail gouges is the amount of steel left under the flute. More steel under the flute allows you to grind a longer bevel on the end and create more detail while using the long point in some ways that emulates a skew.
I use detail gouges in a variety of ways. I have a couple of detail gouges from Packard Woodworks. One has a long bevel and the other has a short bevel. I use the long bevel for exterior shaping of some of my boxes that have globular shaped bodies. The one with the short bevel I use for hollowing and cutting end grain. More steel under the flute allows me to reach farther into the body of the box when I am hollowing and have less vibration.
My favorite detail gouge for hollowing is the Henry Taylor 1/2" which really has a lot of steel under the flute and allows a full cut with the shortened bevel without any chatter. I use it for rough work and then do the fine work with the Packard tool. I like the shape of the flute on the Packard tool for clean up inside a box better than the Henry Taylor.
The other detail gouge I have is the 5/16" P&N I use with a long bevel to reach into areas where the size of the other gouges would prevent access. The long grind on this P&N really is a substitute for a skew. I can peel off shavings of end grain that resemble frog hair!
I do not know if this is how detail gouges are supposed to be used but this is how I have adapted them for doing what I want to do for turning boxes.
I am contemplating pulling the trigger for the Doug Thompson 7/16" detail gouge that has a really shallow flute and see how it does for hollowing. If I don't like it I will regrind it at a long bevel and use it for detailing. Now that is an original thought.
Here are some pictures of three of my detail gouge grinds. In the first picture with the side view from top to bottom is the Henry Taylor 1/2" and then the Packard 1/2" both ground for hollowing. The one at the bottom is the Packard 1/2" ground for work on the outside of a box as a traditional detail gouge. The second picture has the tools in the same order but shows the difference in the flutes. The narrower Henry Taylor flute really makes for a great hollowing tool.