But what carb / manifold would you suggest?
It will always come down to dollars - or euro in your case - that determines what you'll do.
I like DCNF pattern carbs on the sohc, but they can be expensive to buy. The chinese make copies of all sorts of Webers, but I'm yet to see a copy of a DCNF. You can buy IDF and DCOE copies very cheaply, but the quality and finish leaves a bit to be desired, caveat emptor.
There is always the option of a single simultaneous weber, DCNF and IDF manifolds for one carby are out there if you look.
After the expense of buying a carb (or pair of carbs) and a manifold then there will be the expense of setting it up correctly for your application.
Properly tuning / balancing twin Webers isn't something many people are good at, sure they can get them to run - but more often than not they are a long way from optimal. If you've never tuned a pair of twin carbs before it can be a bit of a steep learning curve.
A single simultaneous dual throat carb will be a lot easier to set up and half the expense in jetting components. But many people even find this difficult to get right, and not just your average lay person, I'm talking people who are trained mechanics, have a read of a few threads
here,
here and
here. These days I think any mechanic who's under the age of 45 would have very little experience with carburettors.
Bike carbs are another possibility, but apart from needing a bespoke manifold, then there's the whole issue of tuning them properly to suit... they may come from a similar capacity engine, but a bike engine will turn a LOT more revs... at low air speed they give all sort of tuning issues, and finding someone who knows how to tune the particular type of bike carb you use is even more difficult than finding someone well versed in Weber tuning.
For me the best bang for buck option is a single DCNF pattern carb, I've put one on top of a modified stock manifold for the lemons racer I'm building, see it
here
SteveC