How do I modify the scale so that a graphic in Inkscape which fits nicely in a 158x158 mm area is rendered correctly in a 1024x1024 texture? After hours of scaling using various methods I am lost.

Did you try with a ViewBox as in here?

Yes, but Viewbox only changes the clipping boundary and does not scale the graphics. But that was using a viewbox which was already there. I will try to follow the instructions in the link and report back.

If you put the ViewBox in the root it will scale everything under it.

Will do that. Thanks.