Induction heating theory will tell you that more turns are always better.
Induction heating theory will tell you that more turns are always better. But there are some practical limitations of the voltage available inside the power supply. The cooling capability of a smaller tube being used to create more turns. There are a number of variables that play a role in the design of the process. But theoretically, more turns are always better than fewer turns. To get more turns in the same area you might have to go to smaller tubing size which might limit the water flow. You may have to then split the water inside the induction heating coils to have multiple parallel paths so there's always a way out. It all depends on the gain of efficiency: what is achieved and what savings are achieved.