Talk about overkill, btw Doflamingo isn't supossed to be taller than the Admirals, if anything he's a about the same height or a bit shorter than them.
so, with some operations, I found out that: 1)admirals are all 11 feet tall (three meters and a half) 2)Doflamingo's 10 feet tall (three meters) 3) Kuma and Moria are exactly 20 feet tall (6 meters and 10 cm) Yeah that's great xD Ah...Sengoku and Garp are 9 feet tall (2,75 meters tall)