Moving that much gold makes me think that’s a great opportunity for the world’s biggest heist!
That gives us ~2.7 Minis.
If we factor in the weight of the driver, then we can comfortably get away with 4 Minis, each taking 312kg of gold which leaves us with 138kg per Mini for the driver and any gear that might be needed for the heist.
When large quantities of gold are actually transported "at once", it usually happens in secret on warships. Maybe military planes would be used nowadays? Who knows. Good luck anyhow.
Also I wonder if the rising gold price would interact with this, though I think this would make the "sell and re-buy" strategy actually more viable, at least if you buy first and then sell.
(well, not really, as it weren't direct gold reserves but gold-backed dollar reserves)