Good response Autosri.
Static testing should be carried out using a 50 nitrous jet and appropriate sized fuel jet.
You need to know the fuel pressure (which should be in the 5psi region), to be able to determine what jet size to start with.
It is also essential to know what the bottle pressure is to be able to judge the results, as a poor result can be attributed to low bottle pressure (rather than a problem), if the gauge indicates that to be the case.
Adding a heater is the best way to ensure consistent results regardless of weather conditions.
It would also be worth replacing the nitrous filter, as that might be restricting the nitrous flow.