My classes have always been small, so we rarely do the forms together. I like to let each person work on what they need to in the form. Of course, you can't do that if you have more than a very few people, unless the room is huge. I'm hoping at the new place to have that problem.In my personal practice, I like to change up the rhythms in different ways, to focus on different things. Sometimes I slow everything down, sometimes I speed everything up. Sometimes I will swap and make the quick moves slow and the slow moves fast. Sometimes just randomly adjusting the rhythm as I go.
Sometimes, I focus on the stances, so I will make each move individually and hold it. Other times I want to work on the transitions between the stances, so I spend less time in the stances and more time in the stepping. By randomly messing with the rhythm, I can find out which transitions I can do quickly, which I have better balance in and really identify problem areas.
In class, I do the rhythm given. In my personal practice outside of class... I play and learn.