Always been bugged by the presumption of "gear inches". Mostly because tire selection, profile, and wear plays into the actual number of inches a ratio will produce. Ratios are ratios. Gear inches is a Major Taylor vintage holdover.
Last few years I've been using a spreadsheet printout to determine ratios and also to figure out at a glance if I needed to add a link or remove a link to make a gear combo work. For pursuits I fine tune things a lot more than for mass start events, and this was a quick way of getting where I wanted.
I also set up a side chart to figure out the approximate range you'd need in "typical" road gears to produce a similar ratio during training. Of course I'm shooting myself in the head a bit because again, tire circumference plays into this, but it's at least ballpark.
Here's a zip of the excel file.