There is an SMT/HSL library (Labware_Property_Query.smt) which you can use to get the .x file path in Venus. It uses some if statements in the “Venus language” to determine input parameters and then calls the LookupDataDefValueAsString from the HXCFGFILLIB.HxCfgFile object. I assume you could do all this in C# and get a path to the .x file you’re looking for.