i agree with your train of thought. As for cutting out, i've made reference to were exactly the hole is to be - so avoiding known joists. i was just woried that the plaster saw would shatter/crack the new surrounding ceiling skim plaster.
the plaster shouldn't shatter or crack if it has been applied properly. use a good sharp hole saw (won't stay sharp for long if you are drilling through plaster all the time!) and go easy. should be no problems. i agree with kbrownie - skim first it will make for a tidier job.
DIY how to tutorial projects and guides - Did you know we have a DIY Projects section? Well, if no, then we certainly do! Within this area of our site have literally hundreds of how-to guides and tutorials that cover a huge range of home improvement tasks. Each page also comes with pictures and a video to make completing those jobs even easier!