Online 3d software apps are horrid

[fred_dot_u]

I think those numbers fill in all the blanks. One important observation, though, is that most manufactured electronics today are on boards that are measured in metric. You've provided Imperial units, converted as you said to metric. There's going to be some errors in the conversion, especially when you 3D print this. You may want to check the manufacturer's specifications for hole placement, to see that they are likely measured in millimeters to the whole number and not to decimal equivalents from Imperial units.

Because I'm using Solvespace for the drawing, it toggles easily between metric and imperial, but the OpenSCAD model will be in decimal millimeters, to two decimal places. It's not necessary to stretch it out to three or more, simply because a 3D printer isn't going to give you that level of precision anyway. That sort of logic will probably get you through any rounding errors from imperial to metric or the reverse.

I hope to be able to put some time into the standoff placement in OpenSCAD today and will post if other questions arise.

If your calipers are converting one inch to 25.62 mm, it needs to be replaced or repaired. One inch is 25.4 mm.