I am trying to use the getroute command, specified as such:

getroute id msatoshi riskfactor [cltv] [fromid] [fuzzpercent] [exclude] [maxhops]

1. Do I need to include all the elements above, or can I ignore the optional elements (which I understand to be the ones in square brackets) and rely on their default values?
2. If I can ignore the optional elements, how do I do that?
3. How can i specify the exclude parameter? I had an error trying with:

   getroute 024...a67 1000000sat 10 exclude="687193x890x0/0, 687193x890x0/1"
   

(I am using Spark wallet's RPC console, FYI.)