Defence over

Transfer preempt on level 3 or 4 (3♣ shows preempt in ♦)

dbl (over 3m)    =    14+, balanced

dbl (over 3M)    =    14+, 5+card in doubled suit

cue (tr)    =    T/O (4♣, if over unknown m after 3♠ opening)

3NT    =    tricks and a ST

other   =    as over standard preempt