If the new part is built from some type of template, so all the dims are the same variable label d1, d2... then you can drive those into custom Parameter field name "Param1", Equation "d2".(or in a sketch d2=Param1) Check off as Exported, Rclick and customize the format to be "in" or "ft" "fractions/dec". Then create a Custom iProp name "Prop1" with value "=<Param1>" You just need to find which "d#" is your overall width, height, and length variables.
Your Custom iProp "Prop1" can be used as a column in your BOM and will have the number format you stated in the Parameter option. If the template is setup this way then all new parts will work. The editing of the sizes/lengths can be driven from the sketch/extrusion to the Parameters or from the Parameters to the sketch/extrusion depending on where/how you use the variable names and how you want to edit from one part to the next. If you have existing parts there are iLogic scripts to create Parameters, format them, and create Custom iProp. Your drawing template/style settings can have the BOM setup correct with the custom iprop included.
if you share an example of the part I can show you how to get a BOM column to show "Width x Height" and another "cut length"