.... than the 14" one for sale on the site.

I use either 4 or 6 cinder blocks (usually the ones painted white). I sit a 16" concrete paver down on the ground at the right location (usually 8-10" from the exterior wall) and make two stacks of blocks on either side. I then might put another paver right in front of the first one.

Then I cut pieces of pressure treated 4x4 about 36" in length. Lay 4 of these down spanning the blocks with a 1/2" crack in between for drainage, and you get a nice deck to place your barrel on. A full barrel is very heavy -- sitting it on some leg contraption isn't distributing the weight well. Make sure your blocks are sitting of something pretty solid, such as leveled clay.

By putting the paver (or pavers) on the ground right under the barrel you get a good place (high enough) to sit your watering cans. Plus, the higher the better -- gravity vs. head pressure, you know.