50 mile contrail?

I saw the effect uploaded to avsim yesterday to make contrail approx. 50 miles long. Instead of adding a contrail= line to every plane, I'm considering just replacing the default effect with the new one, but I'm wondering why that isn't suggested in the readme? (Maybe it was an my reading skills are diminishing from reading these forums)Otherwise, is there an easy way to add a contrail= line to every aircraft.cfg automatically?Thanks,sg