My suggestion is to take the time to apply materials & appearances to the SolidWorks parts. The advantage is that the parts will probably be used in several assemblies, so this is a one-time task. (You can also configure those appearances at the part level.)
Now, when you import the model into Visualize, the appearance grouping will be possible. Now it is easy to tweak the appearances in Visualize.
Tip: If your part has several materials/appearances, make it a multi-body part, or you can apply appearances to faces, etc.
Because Visualize is linked to the model, later changes in SolidWorks will be tracked.
Matthew - despite the tool-tip indicating it is specific to alias .wire files, you should give "Group/Appearance" a try. It's not perfect, but does an OK job in some cases of retaining your SW model hierarchy, without going down to the level of every single face as Retain Structure does...which is problematic in terms of how large the tree can grow and it's impact on overall performance.
I can say we are looking to make some improvements, specifically for SW datasets, such that the SW model tree can be precisely maintained regardless of appearance assignments. I can't say when, but this is a high priority item on our radar.
I've been playing around off and on for a couple weeks and have made some decent progress recently.
Basically, my problem was stemming from the fact that I was exporting large assemblies out as Part files first, then importing to Visualize. I thought doing so would simplify the models, but it turns out Visualize handles our large assemblies much better than I thought.
Seems like when I import the assemblies, the "automatic" setting actually works just fine. So this was pretty much on me, I believe!
Thanks for the response