Every product to have a field into which a number could be put and the display order is based on this number so that I can get some towards the top and others towards the bottom.
If two fields then I could have one for say the category and then the other for within that category
Visually it might help if the first was letters and the second was numbers
Then when there was a display that involved more than one category the user would get a certain one first.
Just found popularity which I suppose covers this.