Dimensions of multi-prim objects?

I'm making some pillars for a house I intend to build on a piece of land I bought. These pillars will come in two or three different types, but I want to make sure they'll all be the same total height. How do I go about finding out what the complete object's height (with the prims stacked on top of another) is?

Simple way would be to build another prim (e.g. a cube) by the pillar, align them, and stretch the cube out until it meets both ends of the pillar and take the measurement from the length of the cube. Backwards, make a block the height you want your pillars and build to that.

Less simple way, know the dimensions of your parts. Edit each linked part to find out its height and add them together, assuming they line up and don't intersect. The other way round, if you're building to meet a height - you want the whole thing to fill 10m? Make the pillar 9.5m tall and the ends .25m and make sure their edges match up exactly with a bit o' maths.

You can easily measure the exact size of any object (or group of objects) you own. Simply select the object(s), and then either click "Stretch" on the editor or hold down the shortcut, ctrl-shift. Take a look at the info bubble at the top center of the screen. You'll see the dimensions for X, Y, and Z for the selection. You can also get the rotation of the selection by clicking "Rotate" or by holding the shortcut, ctrl. Location will appear by default if you don't press or click anything.

Thank you.