Out of curiosity, were the tanks on the Gnat fixed "slipper" tanks or true "drop" tanks?
They don't have any fins at the back end to prevent tumbling which I associate with proper drop tanks. I do know
that when the Hawk entered service the legs it had compared to the Gnat was huge, such that the Hawk didn't give the studes a true awareness of fuel burn, even at low level, and so never needed drop tanks unless on a long ferry flight.
MB