RTFM H(elpfiles)That really helps :D
SO: first your output is decimated but you don't need the filter because this vi already do the filtering :)
SPAN defines half the filter bandwidth AND the output samplerate.
together with your original samplerate you can now do your sine amplitude scaling....
However my father has a cochlea implant and the way of exitation and how it affects the hearing nerves is different. But you can se it as a nice programming tutorial ;)