One approach is to simply use a little bit of inference - starting with the info that the system used for the screws, nuts & whatever in the kits has them getting bigger as the number increases - so #4 screws (or nuts) are smaller than #6, which are smaller than #8... So, if you take the parts list - and sort the screws & nuts by size, you can map it all out. Even though I grew up with this system, I've never bothered to figure out the actual measurments - just use this method.
The Metric system is so much more sensible (especially since my background is engineering).
Hope this helps.
Rich