How to hold a gauge in a pod

do you want them to be permenant? If so, how about some CA glue and accelerator spray?

I've used Autometer gauges for some time now, but for the mast part we install them in one of the "A Pillar" pods mentioned above.  The gauge assembly pushes into the hole in the pod and a "friction fit" will hold it very snugly.  There is still enough to remove the gauge and reposition it. but once it's in there, it's pretty much there to stay.  I have never used any kind of adhesive, or tape, or anything else to hold them

I think "secret" to how the pod holds so tightly is in how thin and flexible it is.  I think the gauges are also very gently tapered, at least right under the collar.  The hole for the pod is just slightly smaller than the OD of the gauge, and when the gauge is pressed in, the plastic stretches and holds the gauge with pressure.  Keep in mind, some gauges probably need to be attached from the back with a "u shaped" bracket, but all of the gauges I've worked with allow this "friction fit" approach to work.

If  you can, when you design your console, try make the fiberglass a little thinner around the gauge holes, and a little smaller.  Then, test fit the gauges and adjust the hole size with some fine sandpaper on a large dowel to make a perfect fit.

I'm working on a similar project for a custom gauge enclosure, and this is what I plan to do.  I'll post my results when I get done.

I would try to hot glue it in the back.