Hi BrianP,
Based on your post above, the top and bottom parts (while I have no model here) might need to have an edge selection along the line I have drawn in the image.
This edge selection might be along the edge of the mold. For this object, the mold was split into two main parts. With no details in the texture, the bottom part can be scaled smaller to have enough room for the detailed top part. Online viewing works best when the data is small.
UV_Unwrap,CAD_20240624.jpg
With this edge loop, the relaxing options are better suited to work towards the model's needs. Some pins help keep it from distorting too much.
There are two options in the Relax UV process:
LSCM (Least Squares Conformal Maps) or ABS (Angle Based Flattening)
Please have a look here for a step by step instruction:
https://help.maxon.net/c4d/2024/en-us/Default.htm#html/11658.html
Scroll down.
Which one of the two to choose? After each iteration, I would take a UV checkerboard image and see how it looks (How to do that is in the link below. The key to the textured area should be a projection that produces an equal texture on any part, which is often not 100% possible.
Think of wrapping an orange with a single piece of paper. Yes, that is pretty much the work of two thousand years trying to unwrap the earth to a flat map. I have a book filled with attempts to do that (Flattening the Earth, by John P. Snyder). I share that, as it often feels frustrating not to get a perfect result, this book shows that there are limits to this game.
The bottom part, so far I understand it, needs no relaxed procedure; it could be unwrapped in any way and scaled-down, which means focusing on the top part and evaluating based on a checkerboard pattern
https://help.maxon.net/c4d/2024/en-us/Default.htm#html/UV_SETTINGS-UV_SETTINGS_GROUP_BACK.html?TocPath=BodyPaint%25C2%25A03D%257CGetting%2520to%2520Know%257CTexture%2520View%257CViewport%2520menu%257CUV%2520Settings%257C_____3
I hope that helps.
My best wishes for your project