To be honest I would not use the regulator you have purchased, I have just had the same quandary basically CO2 regulators (for beer) need to be able to handle supply pressures of 3000+ psi (from CO2 bottle) and regulate delivery pressures up to about 30 psi (i.e. the second dial needs to clearly calibrated between 0 - 30 psi).
I am not an expert, but have done a little research and the above is how I read the situation.