I try and minimise the use of custom variables, making the best use of the existing variables wherever possible.
The quickest way to do this is to use the Variable Generator in Bentley Configuration Explorer (BCE). Having loaded BCE with your current workspace, simply paste the path that you need a variable for, click Generate, and a range of possibilities using existing variables will be presented, this is a very simple example:
If you have not looked at it yet, BCE is an essential tool for any configuration work, downloadable from the Bentley iWare site, Tools section.
To create a custom variable just add a valid statement in your Company_Standards.cfg, typically <My_Custom_Variable_Name> = <some value>
One I always add, helpful when dealing with multiple user companies, is
_COMPANY_CODE = <Your_Company_Abbreviation>
So if your company abbreviation is JKL
_COMPANY_CODE = JKL.
This code can be used to identify company specific files, for instance, sheetsizes.def (which defines the available paper sizes and as delivered includes both metric and imperial sizes). You can edit the file to exclude the imperial sizes then save as
JKL_sheetsizes.def.
In Company_Standards.cfg add:
MS_CUSTOMSHEETSIZEDEF = $(_USTN_SITE)data/$(_COMPANY_CODE)_sheetsizes.def