When they cut Thanos arm off and behead him did they take the glove with them or leave it behind?
When they got all the stones Tony put them into his own made glove and the size adapted to fit the Hulk but later at the end of the film when Thanos was about to do the snap, the stones were now in Tonys glove but the one Thanos had looked like it was not the original one he had made.
I thought that when they beheaded Thanos, it was after he'd told them that he'd already destroyed the Infinity Stones?
As for gauntlet size, the damn thing is magical. I'm sure it can fit any wearer.
The Endgame gauntlet wasn't magical. It was Stark nanotechnology.
It's actually a bit clever, plot-wise, to have Hulk do the snap. The Stark gauntlet changed size to accommodate Hulk, but was obviously severely damaged by the snap, remaining stuck at Hulk's size. Which conveniently/inconveniently enough is also the size of Thanos's hand.