I hope this explanation helps in understanding the "G" gauge delima of using after market parts.
Lots and lots of items come in a variety of size- door handle-water bags - Pipeing and on-on
We have adopted a color coded system that shows what scale item can be used for.
We have also added a symbol to show what is the primary scale for the item. So if your looking at an item - Say a monkey wrench - I may have been made for 7/8ths scale but works in all scales
In 1:29th scale its about 3 foot long, in 1:20.3 scale about 14 inches and in 7/8ths about 10inches.
You can learn more about scale -Gage and using parts in multiple scale to create very nice illusion
If you ever have a question please give me a call at 435-586-1036