Th e comparison get a little complicated, the emporer has a straight onle form bushing to bushing. The bushings are the same size for each end of each barrel for both the upper and lower barrel. the Havana tapers for both barrels, The bushings are smaller at one end of each barrel.
So my comparison is against the largest diameter of the Havana upper and lower barrels.
the Emperor cap is the same diameter but longer than the Havana.
the lower barrel is larger in diameter by a fair bit and very close to the same length.