To overwrite the default set of parameter, please edit multi_params.json file and add a dedicated named testcase or edit one of the existing ones, e.g.:
"test_my_design":{ "DATA_TYPE": "cint32", "COEFF_TYPE": "int32", (...) }
To run a testcase, please specify the testcase name passed to the PARAMS argument, e.g.:
make cleanall run PLATFORM=vck190 PARAMS=test_my_design
For list of all the configurable parameters, see the Library Element Configuration Parameters.