MP, robodupe, 34
Most of the room bought it in 3H, by choosing 2H initially over North's double. North then competes to 3H over 3D by oppo. End of.
Perhaps I was being too clever for my own boots. 2S and 2H were about equally likely to hit the best strain, but if it does not die there then starting with 2S improves our chances of playing in whichever major is better.
There are two points of interest, I think:
One is that South having bid 2S North should never expect my subsequent bidding to indicate a hand too strong for the earlier 2S. If North thinks that game is on over a South that is worth 2S he should not risk defending 3D. I am curious to know whether North would have passed me out in 2S had West passed instead of 3D.
The other point of interest is that I don't think that 3H can sensibly show systemically as few as 3 cards in the suit,