Two-Under for One or Both could also be used with an alternative style of Multi, if one were so inclined.
Consider a standard 2C approach. Many use 2D waiting, plus Kokish. Thus, with heart hands and strong balanced hands, Opener starts with 2C, bids 2H, and then makes a call at the three-level.
Well, suppose, then, that your TWO CLUBS opening were multi, showing:
1. Weak with hearts,
2. Weak with spades,
3. Weak with both majors, or
A. Very strong, balanced
B. Strong with hearts primary
In that structure, Responder would assume weak and would normally bid:
I. 2H with heart preference
II. 2D with spade preference
If Opener has weak with majors, Responder's preference ends up the spot. If Responder has just spades, he bids 2S next whatever Responder prefers. With just hearts, he bids 2H or passes if Responder prefers hearts.
If Responder preferences a major but Opener has the strong hand, he next bids 2NT or higher, which shows the same thing that would be shown had Opener started a standard 2C, heard a waiting 2D, bid Kokish 2H, heard the 2S relay, and then bid.
If Responder has extras, sufficient for a game try opposite the weak hand, we are probably bidding a grand opposite the strong hand and can work it out. But, assuming a weak hand, Responder can bid 2NT as an unwind. Opener with a maximum for a weak hand bids 3D with both majors or his one major naturally. With a minimum weak hand, Opener rebids 3C instead, and the same unwinds normally available are still available, just one level higher.
Responder with one-way extras bids 2D with interest only if Opener has spades and then bids accordingly, or with a hearts-only interest bids 2S as a paradox bid. This seems somewhat better than regular multi because only one suit requires paradox bidding, and you get the bonus of the two-suited major hand.
If Opener has a strong hand of other varieties, he opens 2D, with 2H as the relay. This does not preempt anything, because the hands where Opener would have wanted to rebid 2H are bid through a 2C opening. Opener, after the relay, continues normally.
This alternative core for multi players might be better than the traditional approach, in that you ad yet another type of weak hand.
(One might also use the "Rexfordized Kokish" approach with this multi, where the 2C opening following by 2NT is not the big balanced hand (bids those through 2D) but rather a MINOR-major canape hand. See my articles here: http://cuebiddingatbridge.blogspot.com/2010/06/different-spin-on-kokish.html and here: http://cuebiddingatbridge.blogspot.com/2010/06/rexfordized-kokish-part-ii.html and http://cuebiddingatbridge.blogspot.com/2010/06/rexfordized-kokish-part-iii.html for details.)
Any thoughts from multi players?