Moed Katan 10 Millstones and Food Preparation

There are a lot of things that I don't know.  Of those things, I know more about just about anything than I know about millstones of antiquity.  Today's daf offers an insider's view to the ins and out of the millstones used to grind grain into flour.

We learn that it is permitted to build a stove on the Moed.  We are also permitted to service a millstone.  Both of these activities are critical elements of food preparation, which is also allowed on the Intermediate Festival Days.  But what exactly are we permitted to do?

The rabbis note that the millstone might work in a number of different ways.  The stationary circular stone likely needs no repair, but the upper circular stone may need modifications - it may have grooves or a rough surface that require maintenance.  As well, the hole into which whole grain is distributed might need servicing.  The rabbis discuss whether our Sages were referring to one or more parts of this stone.  

We learn about millstones that turn using the force of water.  I am curious about millstones that require animal or, just as concerning, human force to operate.  This job of moving in circles would have to be described as arduous labour.  Would the rabbis consider that work to be permitted?  

We also learn that the work permitted should be work that can be done without the expertise of a specialist.  As soon as a 'professional' is brought in, it seems that we enter a different category of labour.  

Again I am reminded of the work that is permitted to prepare food.  Why is this labour, generally done by women, unquestionably permitted?  And rather that ensuring that food preparation is as simple as possible, our halacha permit 'loopholes' so that women can do even more work.  Creativity is encouraged to ensure that food is as exquisite as possible on Shabbat.  But this question is part of a much larger discussion about gendered divisions of labour.