After the T-port sync has been set, you may find the idle-timing down at say 12*. Well this is gonna make big trouble on the choke system. Now it will be more important than ever, to have a good working VA, AND THE BIGGEST ONE YOU CAN FIND,usually about 22*. And that is also why I recommended the 2-stage timing curve.
If you can't get the VA to work off the sparkport, while the engine is on the fast idle, you will have to hook it directly to manifold vacuum.