Well lets all be thankful your notSmoker Tom wrote:Wait a sec.....
On the ones I have worked on.
I drill a 1 inch hole and the 3/4 nipples screw right in. I am not sure how close you can get using 1 inch nipples.
OMG.....If I was a plumber, I think that I would prefere (close nipples) Actually, right now any would do!!