^ That is exactly what I do with my Fincar.
It takes a bit of practice but it's not THAT hard..
You won't get exact size pieces, but I don't think it matters, as long as you finish a whole pill within a 5 day period.
I think that since the effective dose of finasteride ranges, that it won't make a huge difference going from less than 1mg (small piece) one day, to a little over 1mg (bigger piece) the next day.. the variation shouldn't matter imo.