Do you plan to use these hashes when searching for new
instances of the file that become available as connections
change, instead of looking for the file name, size, etc?

'Cause if you're not, it would probably help reduce bandwith
and CPU use on peers by only sending/matching a few bytes
instead of the whole file name, size, etc, and also increase
the number of instances that could be found because even
files with wildly different names could be matched.