Wolff Signoff After 2NT Rebid

A friend from Chicago recently asked me to post notes on the system that I use with Joe after a 2NT rebid. Transfers are popular these days, but I've had decent success with this, so here it:

applies after 1m-1M-2NT start, not after 1H-1S-2NT or 1C-1D-2NT
3C=relay to 3D (usually some slam try but could be to play 3 diamonds)
After opener accepts the relay, responder's bids:
3 of bid major=6+ suit, slam try
3 of OM=slam try in minor not opened
3NT=slam try in opener's minor

3D=checkback for majors (opener bids hearts first)

3 of bid major=signoff, 6 card suit

3 of OM:
over original 1S=5-5 or 6-5 forcing
over original 1H=4/5 forcing, slammish--partner cues clubs with good hand for hearts and diamonds with good hand for spades