Sounds like fun! Won't be able to join the team myself, however.
Sadly, we know very little of units of length smaller than one 'uj, but yes, there is confirmation of those measurements being expressed using decimals. In the link above, you'll find examples such as
wejvatlh loSmaH loS vI' vagh wej 'ujmey (344,53 'ujmey)
> Should a Klingon ruler double as a weapon?
Depends on the end-user, I suppose, but I personally would advise against it; rulers are rulers and weapons are weapons.