I agree with Old Scrambler on the two key issues. The engines are physically too far apart, and it is likely that one will be nominally stronger than the other.
If the hose is a foot long, you’d wind up with better than a ½ ci column of air/fuel mixture, along with its associated momentum, affecting manifold volume by moving back and forth, possibly out of sync with what the engines are trying to draw.
If you're running vacuum advance and seperate ignitions, you would want to keep the two seperated.
In your case, I think you should maximize output of each engine individually, and give each what it wants as far as tune is concerned.
I’m sure that they will be close as far as output is concerned, but equal power is not necessarily the goal. Maximum power from each engine is. Seeing as there is no way to perfectly match power between the two without compromising the stronger engine, I wouldn’t try.
I’m not saying don’t try the tube – if that’s what the engines want, that’s what they should have. I don’t see it working, but I don’t know for sure.