Any time you swap the tube in a monitor, you really ought to keep the deflection yoke with the chassis. Even if two yokes read close to the same in terms of DC resistance (what you're checking with the meter), they aren't necessarily the same when it comes to inductance (what the chassis cares about). A monitor's deflection circuitry is designed to operate with the yoke that goes with it. You can't be certain that it will work properly with a different yoke. Sometimes it'll work, other times it'll work but the screen geometry will be off and you won't be able to adjust it out. Other times if the yoke is way off, you'll simply burn out the deflection transistors in the monitor (usually this only happens when the DC resistance is way off too...).
Some chassis have deflection circuits designed to work with a range of yokes - and a host of controls to compensate for differences. These are generally the aftermarket replacement chassis, like those 8-liners ones.
But, when it comes to replacing the tube in, say, a G07 - just swap the yoke over. Yoke stays with the chassis, rings stay with the tube. Before you remove the yoke from the old tube, mark the top such that it lines up with the anode connection. Line it up the same way on the new tube. Mark the rings on the new tube so you can put them right back once you've swapped the yoke on.
-Ian