vac port under idle adj screw

Hi guys,
Hope someone can shed some light on this for me.
I have some rough idle problems with 86 cabrio 1.8 gti. After all the usual checks I found there was little or no vacuum out of the port under the idle screw in the throttle body. The other end is attached to the dizzy advance.
I re-routed the hose another spot at the one way valve and hey presto she runs sweet.
Problem solved, well yes, but thats rises other questions.
What is the correct connection for the dizzy vacuum?
What can I do to clear this small port I have had carb cleaner in there and there is a tiny draw but to me its not enough to advance the dizzy.
Does anyone have any insight as to the internal construction of the throttle body as when I put a small punch into the vaccuum it bottomed out so can only get fluid in from the outside.
Any help or chat on this subject would be of great help.

If it aint broke…

dizzy vacuum should be connected to one of the nipples on the brake servo chunky pipe. these like to snap so this may be why it was moved.  the tb ports can have little vacuum depending on which side of the butterfly they are located on, also they can be really clogged up with oily shizzle which requires poking out before it'll clear