Set your Poser units to centimeters. Then you can use yTran as your measuring scale.

Take any prop sitting on the ground, dial it's yTran to 100, and it now hovers exactly 100 cm or 1 meter above the ground

11 feet = 335.28 centimeters, so just set the yTran dial to 335.28 and you're there. Couldn't be easier than that.

But again, this works ONLY with metric units, and especially centimeters.

Likewise if you want a "universal yardstick", just scale up a cube primitive until it's exactly 100 cm large, re-name it and place it on the ground and then save that "meter-prop" back to the library.

Load that meter prop, and its scale dial will now show 100%.

You want to measure 156 cm? Just dial its yScale to 156%. You want to measure 11 feet? Just dial its yScale to 335.28%

You can of course DIRECTLY measure in any direction by using the y-, x-, and zScale dials of your "meter-prop" accordingly.

Here's how the most common Poser girls load directly from the library once you "Go-Metric". (Aneta is a custom character I re-sculpted using real-live proporitions of an actual women)

As I said, once you "Go-Metric", there is no coming back, because this allows you to DIAL DIRECTLY any scale using the Scale and Trans dials without any need of conversion in your head.

;-)