I am getting ready to put up furring strips on my basement ceiling so all of the pipes are hidden. I am going be using 2x4s laying flat. If i put them 16" oc then they high hats dont fit. Can i do it so they are 24" on Center? or 18" oc. I don't want to make more work for the drywallers. I am afraid if i do it 24" oc i will have sagging issues down the line which i dont want.