Uniform uv unwrapping

I’m having difficulty in getting a nice uniform uv unwrap. I know uv unwrapping can be a huge pain for even a skilled modeler, but if someone could help me find a way to get the unwrap to be more uniform with less stretching. The problem lies with the rim and the outer edge of the mesh what is to be a metered gauge. The circular parts are fine. I just can’t get the uv to properlyevenly unwrap on the rim and outer edge. All seams are visible in the picture. I’ve tried placing seams in various different ways, but I’m still not getting the results I want.