EPSP/IPSP amplitude values?
By definition, current-based synapses are biologically implausible.  After all, biological synapses are conductance-based [1].  It is possible that current based synapses are sufficient to answer the question you are asking.  It is also possible that they are not.  Generally, biological plausibility is not a matter of the parameter values you are using but rather a matter of whether the question you are asking has biological relevance. After all, unless you have a morphologically accurate simulation including every single receptor type, etc. your model is not biologically realistic.  

The question you are asking doesn't have a good answer because you are asking a biologically non-sensical question:  what is the value of current based synapse magnitudes?
The only way one could possibly answer that question is if one knew why that question needs an answer.  Maybe you don't even need a reasonable value for the question you are trying to answer because the phenomenon is robust.  Maybe you need the answer to the fifth decimal place because your model is very sensitive to that value.   

Point is, biological realism is incredibly context-specific.

[1] Although I have heard a strange argument that the high resistance at the spine neck means that synapses are practically current sources.  I don't know anyone that relies on that.