Years ago I built a spread sheet in Lotus 123 to use for scaling frames and other items as I scratch build.
A few years ago, I built the same spread sheet in Microsoft Excel.
If you run Excel, you can download the simple to use spread sheet from My GW sub picture page.
It's near the top of the page in a green box.
In fact if anyone finds this little spread sheet useful, you're welcome to it. Easy to use and easy to modify.