Easily Add Power with Tunit Tuning
Tunit provides an efficient and adaptable method of enhancing a vehicles performance (power and torque) without the need to alter the vehicles original equipment or programming. The advantages of the Tunit are; adjustment for optimum efficiency (both manually, by the customer and electronically, via a PC by a distributor), flexibility, as in movement from one vehicle to the next and ease of installation. The principle of Tunit is to provide all these advantages that previous methods of tuning such as EPROM replacement and "flashing" or OBD tuning could not. [Complete Article]
apparently, if your car runs, then the person who installed the carbs corrected the float bowl angle to be what Good Times was referring to (the rubber "donuts" that go between the mounting bolt and the float bowl housing are specific to the mounting angle for the carburetor (mini and sprite engines are tilted differently) and without changing these the carbs from a sprite will not work on a mini, but once these simple parts are changed they most certainly do).
I've never measured the distance that you are asking about, but I strongly suspect that the twin carb setups for both a sprite and a mini have the same distance (since the distance has more to do with the breathing of the manifold than anything else).
The good news is that you can easily make a new distance piece if you find that there is a problem (remember that the throttle shafts just go "through" the carb itself, and each is connected to the distance piece by that wavy shaped clamp. This piece of steel rod is available at any hardware store if you need a longer one for any reason.