At this stage it is not immediately obvious what the wheel array is doing,
Nothing at the moment but at the end of the game you will want to flash all the chosen symbols in turn. If you don't store what the results of the three wheels were you will loose them and ot be able to get them back. You might also want to register some combinations as a win and without knowing what all three are you can't.
When I run the code now the serial monitor confirms that rows advance with each spin but the spinCount is uninterrupted by each spin, the rows change but columns just keep ticking along.
Sorry I don't understand what you are saying here.
thought that the print.ln command was a silent observer
It is.
seems it can be an active player too.
The only thing a print statement can do is to slow down the code, so if you observed something different then maybe your code was not like you thought it was.