Trails
OAP
I'll try-the Tristar as you point out has only one hose usable so it must have a plan for sequential refuelling of all rx. For a 2 hose tanker it is possible that a plan using refuelling of rx in pairs would make for a more feasible option (eg the single hose version would require an inordinate no of small bkts ). That does not mean that as a back up plan such a situation is unacceptable, simply that as a main plan it would not do. Equally the crews have procedures to go from 2 hose to single plans without a formal plan being issued.
As far as the other issue of length of deployment is concerned , the Voyager range/offload advantage comes to light on sorties exceeding about 5 hours, the main problem to be honest is that of FJ limits esp crew fatigue etc. With the possible exception of the South Atlantic route , shorter but more palatable legs are usually available.
Of course the more FJ back up you put on either ac, the less fuel you have anyway.
In sum I doubt the Voyager will do legs on trails that are much longer than the Tristar but may have more ex per tanker.