Internally we work with metric units and use decimal fractions for sub units, e.g. 1cm or 0.35cm or 23mm)

We're building a user oriented design tool for laying out reports and was wondering what the most most common approach taken by UI developers who are still working in Imperial measurements (Inches etc.) when it comes to decimalised fractions.

Most of my cultural references point to people using 1/2, 1/4, 1/8 or 1/32 inch when measuring fractions. But when faced with decimal equivalent what do people tend to do?

For example do people use 0.5, 0.25, 0.125 etc or do you people roll these up to say 0.5, 03, and 0.1 inch?

Sorry for the confusing question.