Boat up on the hard, the owner wonders how tall the mast is??? The yard-worker, spotting some easy money, says "we can take the mast off and lay it on the ground". The owner says, "I don't want to know how LONG it is, I want to know how TALL it is". Chicka-boom.
The standard rig has a I of 25'. Note at the bottom under the notes and you'll see the I is 29' for the tall rig. I is the length from the highest halyard to the deck (Or where the deck would be without the cabin) on the front side of the mast. So run a tape up on the jib halyard and see what you get. You have to fudge a bit about the cabin but the tall is 4' ft. longer.