OK, I've put this job off all year while it was warm. I need to insulate
the garage/shop attic. I have about 500 SF of attic space to insulate and
the joists are 2x12 on 16" centers. I'm trying to decide between cellulose
and fiberglass. From what I can determine, cellulose will be cheaper to
install and may perform better. In fiberglass' corner are built-in vapor
barrier and maybe easier to deal with overall. Here are the questions I
have.

1. The manufacturer's instructions for cellulose only state the blowing
machine as a method of installation, but a few places on the net that I've
read state that if the rafters are exposed, you can just cut open the bags
and essentially dump the stuff in. Can anyone confirm one way or the other?
2. If I use cellulose, do I need to put down a plastic vapor barrier first?

Anything I'm missing?

TIA,

todd