I'd be leaving from Manchester Business School (West), so Mauldeth Rd is pretty much a no go, might as well take the train from Ox Rd (and change at Piccadilly if faster).
I'll still take the bus on the 14th just to see what it's like - with plenty of time to spare.
By the way, does anyone know of any shortcut between the Station and T3? The lifts seem to take forever!