Charlie Yu

North gets around 300% of the blame, at NV it is quite an obvious 2♦ NF if available and 1NT if not available.

5♠. If our side is going to bid game, may as well use my club void to ruff some losers.

Multi 2♦ is pretty much worse than weak 2 major, as responder can't preempt as effective as a weak 2M. Though Multi frees up 2♥ and 2♠ for other purposes. However, if allowed, I would rather play 2♦ Wilkosz + weak 2 major than Multi+Muiderberg.

Definitely. 3m overcall is a very strong weapon against multi.

4♣, no ♦ stopper, secondary support to ♣

I play control showing response after 2C: 2D - 0-1 control, 0-3 HCP 2H - 0-1 control, 4+ 2S - 2 controls 2NT - 3 controls, etc. I would open this 2C so that I know where to play immediately.