1♥-1♠-1NT

After this start, Opener's shape and strength are known to a great extent, much more so than over a classic 1m-1M-1NT start; there are only 3 possible shapes owner can have. Also, 1♥-1♠-2♥ is never used. So, instead of 1 or 2 way New Minor Forcing, we use 2♥ALERT as the checkback bid.

The basic idea is that Responder now bids 2♥ALERT to imply invitational with 5 spades, and Opener responds with something about his hand; using 2♠ as any minimum (2M in a 5-2 fit scores better than 2NT). Responder's bid over 2♠ now creates a force. With 2♣ and 2♦ now freed up, we use them for bad Responder hands with 4 spades and a longer minor that would rather play 2m than 1NT.

The full suggested menu is:

2♣ - to play, typically 4♠, 5♣
2♦ - to play, typically 4♠, 5♦
2♥ALERT - artifical, one round force. Probably but not guaranteed to show 5 spades.
2♠ - to play
2NT - invitational, usually 4 spades
3♣ - GF natural, 5+ clubs, 5+ spades
3♦ - GF natural, 5+ diamonds, 5+ spades
3♥ - 3 card limit raise
3♠ - invitational, 6+ good spades
3NT - to play
4♥, 4♠ - to play
4NT - quantitative invite

Developments after 2♥

2♠ - any minimum. If Responder bids again we are in a game force
2NT - good hand, 2 spades
3♣ALERT - good hand, 3 spades, ruffing doubleton club (?)
3♦ALERT - good hand, 3 spades, ruffing doubleton diamond (?)
3♥ - good hand, 3 spades, 4 heart honors (?)
3♠ - good hand, 3 spades (?)