Best way to do this is really a little at time, I make one cut about an inch before what I belive to be my final messurement is. Then I slide the shaft in there and just make sure the tube is still longer than the shaft.
Your numbers look right to me, but play it safe and cut it under. Your close to building a final axle dont rush the cuts as its a somewhat easy repair to add tube but adds to the time and labor of the build.
1993 YJ 4.0 60 Front, Rear steer 60, bolth spooled, 5.38's, 700r/241 39.5 iroks and beating it like it owes me money.