Are you referring to line weights shown in SketchUp viewports? If so, you can set one line weight multiplier per viewport. That is set using the Line Scale setting. Edges in SketchUp can be normal edges or Profile edges and Profile edges can be set heavier than normal edges so you can effectively get two line weights per viewport. If you need more choices, you can stack viewports and use different Line Scales for each. You can also explode a viewport after Vector rendering it to get LayOut drawing entities. You can then set the weight of those lines in the Shape Style panel. This isn’t ideal if the model is likely to change but it is an option.
Stacked viewports can be easier to work with and with the ability to control which tags are visible and what style is applied to each viewport, it’s actually pretty easy to get whatever sort of appearance you are after.