I originally used 3 circuit carbs and struggled with them so I switched to 2 circuit. But now I find myself going ahead and buying 3 circuit carbs for certain applications with the knowledge that I can always just lean out the intermediate circuit. It can be leaned out all the way to zero if a person wants to so I guess I don't see much harm in having a 3 circuit carb. It is just another option that may or may not be needed for the specific application.

Of course, this all assumes that the carb has billet blocks in it and that the person tuning the engine has a wideband or some other means to see what is going on.

One other point is that the intermediate circuit doesn't have any emulsion and it doesn't flow out of a booster. So it is fairly raw fuel that is being pulled out of the dump tubes. Some fuels (high RVP) might work better than others in that situation. I've never seen any sort of tech writeup on the subject but I think it is probably important. I'm sure someone has high speed video of the fuel coming out of the dump tubes. I've never seen a video myself but I'm sure that the engineers at Holley or BLP have looked at this stuff.