Multiple vertical stabilizers.
If we look back in time, the original design of the DC-4 (C-54 for you AirForce folks) had a triple tail...and with good reason.
The original DC-4 design was much larger than what it turned out to be, so a triple-tail was thought to be slightly more efficient. Prevented 'fishtailing'.
Only one was built.
The DC-4 was down-sized, so a single tail was used.
This info comes directly from the assistant engineering project manager at the time, a close personal relation.
When the DC-6 came along, the single tail was retained (triple-tail briefly considered, but rejected).
'Fish-tailing' was prevented due to a slight wing twist, however the same planform was used (DC-7) as well.
Also info directly from a close personal relation, now the chief engineering project manager.
B377 Stratocruiser.
This airplane, developed from the B-29 bomber (however different engines/enlarged fuselage, but the same basic wing) had a very high single tail.
So much so it would not fit in many hangars of the day.
So, Boeing developed a folding vertical stab...presto, problem solved.