3 circuit should be better than the 2 circuit if the calibration is done correctly. What the intermediate circuit is really supposed to do is act like a mechanical power valve and give the engine a mixture that's about one ratio richer than if it was not in the picture. What happens is that the transfer slot is opened more and more and then gradually starts to run out before the main has a chance to really get going if jetted correctly. BUT we could get the main to start up by giving the carburetor more jet or a richer mixture from the transfer slot and make it work. This will work but it would be better to be able to run less jet and a more correct idle mixture by having another circuit which fills this hole. This is really the sole purpose of the intermediate circuit and it has to be used correctly otherwise it can cause more problems than it solves. Many Dominator packages have this circuit trimmed incorrectly for proper part throttle operation.
Any sufficiently advanced technology is indistinguishable from magic --Arthur C. Clarke