Depends on what you feel is right for your motor....
Personally, I prefer the vac/mechanical advance dissy. They give a smoother idle and better (smoother) acceleration down low without effecting your high speed running. These would be fine on a stock/mild engine, but might not be the best option on an engine with a big cam.
The 009 will work, but most people find that they can cause a rough idle and often create a flat-spot just off idle. The 009's appear to work better with some carbs than with others... although I have heard that there is a mod you can do to rectify this...
With all that said, a working 009 will give a better result that a busted vac/mech dissy 😁
Have a look at any of the parts distributors that you will see advertising here or in VWMA - most of them will have both in stock.
R 🙂
40hp, 6V and ...er... slowly making improvements
😂
It's nice to be important, but it's more important to be nice!
Founding member of the Gold Coast Dub Club Inc. 🙂