A T-40 torx bit is .260" from point to point.
A 1/4" (.250" flat to flat, .289" from point to point)
A 6mm (.236" flat to flat, .272" from point to point).
This makes a t-40 an excellent tool to tap into a stripped 6mm socket head cap screw. The torx bit will hold much more torque than a hex shaped socket.
Give it a try and see.
Some heat is good to release locktite, but heating the aluminum is dangerous. It may damage the case if too much heat is applied. Never use a torch on this application. Heating the screw itself will only make it expand and get tighter.
Heat the whole area with a heat gun.