I can see the problem as I had the same when trying to combine metric and imperial measure. Especially the KM and mile. I used 1.62 to convert but soon found it hopeless.
1 mile = 1.6093km and so converting is hopeless.
In the ancient world the mile and kilometre were compatible as 1 mile 5280 feet = 1600 metres exactly the ancient metre = 1.00584 modern metre.
Some examples 360 modern metres = 1181.1023ft but in the ancient world = 1188ft 14256 inches.
Diameter of moon 2160 miles = 3476.088km but in ancient world 2160 x 1.6 = 3456km as ancient metre 1.00584 modern metre.
Really enjoyed your presentation on Rome and the Bible thanks for the references.
We have the numbers just have to refine. Eventually I bought a Casio pocket conversion calculator. Your royal cubit 52.5cm = 20.669291 inches and everyone has a different opinion on it's length anyway I use 20.625ins 52.3875cm