Natural (2X)

(2Y)-NAT
X!T/O, 12+
2ZNAT, 12–17, 5+#
2NTNAT, 16–18
3XNAT, 14–18, often 6+#
3YAsk for stopper, SOL 7+ suit or STR T/O
3ZNAT, 15–17, 6+#
(2m)-NAT
4m!Leaping Michaels, 5+♠, 5+♥
4om!Leaping Michaels, 5+M, usually 5+#
4NT!NF S/T in om
(2M)-NAT
3M!Ask for stopper, SOL 7+ suit or STR 4+♣ 4+♦
4m!Leaping Michaels, 5+oM, usually 5+#
4M!Leaping Michaels, 5+♦, 5+♣, usually unstopped
4NT!NF UNT with stopper, 5+♦, 5+♣

Reverse Lebensohl

Though usually treated the same, there is a significant difference between (2X)-X and 1NT-(2X): we cannot pass boring hands in the former situation! After a long discussion, we came to a conclusion that reverse Lebensohl with Rubens advances is a better alternative than transfer or standard counterparts.

As opposed to the standard/original Lebensohl, this 2NT relay handles constructive hands (8+ HCP or 7+ HCP by passed hand) while directly bidding a suit below 3X is weak. Since an in-shape takeout is short in the adverse suit, advancer is more likely to have a stopper. Inviting with 2NT right-sides the contract more often than not.

(2Y)-XT/O
2Z, 3XCOMP, 4+#
2NT!INV+, REV LEB
3YZ!INV+ TRF, 5+ next suit
3♠!Ask for stopper, usually a long minor suit
(2Y)-X-2NT-REV LEB
3♣!MIN P/C
3Y!FG, 4+♣
3XZFG, 4+#
(2Y)-X-2NT; 3♣-P/C
3XS/O
3YZ!INV+ TRF, 4= next suit
(2♠)-X-2NT-REV LEB
3♣!MIN P/C
3♦!FG, 3=♥
3♥FG, 4+♥
3♠!FG, 0–2♥