What parameters to use? The answer typically is, it depends on your goal. For example, if you want to compare your model to other models already in the literature, you can use parameters in other studies…those studies you want to compare your paper with.
Parameters can come from microdata… Willi Mutschler warns on aggregation issues.
You can calibrate your model to target some big ratios like C/L, etc. More info here on calibration:
Read also open economy macroeconomics by M. Uribe and S. Schmitt-Grohé. They talk about calibrating
(a) Parameters Based On Sources Unrelated To The Data The Model Aims To
Explain
(b) Parameters Set To Match First Moments Of The Data The Model Aims To
Explain
(c) Parameters Set To Match Second Moments Of The Data The Model Aims
To Explain
You can start here but you can find hints on calibration in several other places. If you calibrate your model based on your goal and interest rate responds little to contractionary monetary policyshock, then I guess it is a structural feature of the model, and maybe consider modifying the structural features of the model, not only parameters.