Yes wet-wing is not sustainable hence we had purpose built internal tanks on both types of aircraft to take the larger amounts in. We did wet-wing on the IL76 once but its takes hours to offload through an outlet on one of the engines.We 'wet-winged' fuel into BSN in the early days - it's an emergency only thing really, not really what strategic lift is for - and even an L100 can't land everywhere!
A number of my service oppos went down on the Supreme thing, lots of military logistic experience, zero commercial nous.
What could possibly go wrong?
Supreme failed because of poor contract management from the military and no robust on-the-ground oversight.