"IF the flaps/linkages are not set up exactly correctly then at best you get little vacuum at worst you get no vacuum AND lots of smoke"
This may be my problem. I have OODLES of smoke and little vacuum. By 'flaps' do you mean the tipping disc (Is that the butterfly?) inside the air intake pipe? The thing that opens when the accelerator is depressed? It does seem to be fully shut when the accelerator is not touched, as it presumably should be, but what adjustment can be made? It is also very oily, which doesn't seem healthy, given that it's meant to be putting clean air into the engine. ???
Also, on that (butterfly?) housing, there is an inlet pipe for a servo hose. There is also one at the back-of-the-engine-bay end of the air inlet pipe. Should hoses be attached to both of these? And another to the vacuum tank? There is ANOTHER inlet on the air intake pipe which at the moment takes a connection from the breather on the rocker box.
Sorry to be so ignorant - that's why I joined the forum!