Sorry Brian 48nav, I'll join Danny in disgrace in the corner of the hangar
As we grovel together, I might recall that Tubby Dash told me of delivering a Sealand to an Egyptian potentate. This one was so luxuriously fitted out that its payload was even lower. It has been recovered to the Ulster Transport Museum, at Cultra a few miles from the Shorts factory in Belfast, and they hope to restore it to static condition.
An ex-Fleet Air Arm friend reminds me that the Percival Prince/Sea Prince of the 1950s (twin Alvis Leonides) also offered Hobson's choice of lifting fuel or passengers. Again from ancient memory, its air supply was limited and could run low on continuous circuit work. As it was steered by differential air braking, this made for interesting taxying.