Sorry, been at work and haven't checked in for a while.
The DGAV is a much smaller carburetor than the 350 cfm 2bbl. Closer to 280 cfm or so. It is a much more appropriate size for your engine. The 2300 series has a different base. Your DGAV is specific to Weber. The 5200 series may fit.
The reason you will end up in the power valve is to keep the mixture from going too lean. In order to cover moderate acceleration, the power valve adds enrichment. Like when you encounter a hill, or decide to travel at 50 instead of 40 mph. Part of the enrichment is the pump shot, the other would be the power valve.
In order to cover moderate, or even heavy acceleration, the power valve must open up to provide acceleration mixture, which is necessarily richer than cruise. To do that with the jets, your economy would tank across the board.
A carburetor that is open more efficient than one that is just cracked open. In order to make that work, the carburetor has to be sized appropriately to the engine. The most efficient way to do it would be to run without throttle plates, like Fiat's new MultiAir engine does.
Do the math for your displacement at the highest rpm you run the engine. That will give you the size you need in a carbutetor.
Now if your racing your 2L, then a 350 CFM could be the ticket. Your going to have to turn it up over 9,000 rpm to flow near that though, and the cam choice will need to be extremely radical. Big compression.
2¢
CJ