I've done a check on the Gulfstream 4 and I do not see a fuel dump valve. There's a drain for servicing but not a master fuel dump.

So, fly low in thick air, burn a lot of fuel. If it was fully loaded, it needs to burn 10,000lbs of fuel before landing. 500gph standard fuel burn .

Not the way I'd prefer to land, but they have lots of time to prep the cabin and the passengers.