for all the help. I've decided to go ahead and get it done without using the furring strips. The ceilings do not wave...the previous owner just liked that textured look. So much so that he even did the garage ceiling with it!!
The person that I've decided to hire is a painter/drywall guy...he gave me 3 references, including one where he drywalled over plaster ceilings, and all 3 references were good. He also said that he would use screws, not nails...I'll know tomorrow when all this will begin. I'll keep ya posted.