2.1 Responses to 1NT

3 & 3♠ — 5-5 in the Majors

WestNorthEastSouth  
  1NT Pass 3 Invitational, 5-5 in the majors
Pass ?      
Pass To play
3♠ To play
3NT Ususally not a good idea
4♣ Slam-try in hearts (lower cue bid for lower suit)
4 Slam-try in spades (higher cue bid for higher suit)
4 To play
4♠ To play
WestNorthEastSouth  
  1NT Pass 3♠ Game force, 5-5 in the majors
Pass ?      
3NT Ususally not a good idea
4♣ Slam-try in hearts (lower cue bid for lower suit)
4 Slam-try in spades (higher cue bid for higher suit)
4 To play
4♠ To play

As with the 3♣/3 bids over 1NT, opener should be very cautious about trying to overrule responder (who is captain) about the level. It is only when your hand is very concentrated in partner’s suits that this is at all possible.