From my experience it really doesnt matter - because unlike noncarnivorous plants - carnivorous plants dont take up nutrients from the soil, just water. So the only real reason to divide them is to cut down on the chance of getting a fungal disease and getting more light down to the base of the plants.

If you want to see the plant flower then I would say just divide them after it flowers.

Drosera Capensis - what you have, is very forgiving generally.

Let them clump. They are so beautiful when they clump.

Here is a old album of clumped Drosera I took years ago. Some of the pics were put into the Sigma catalog for their tissue culture supplies.

Drosera also seem to be more healthy when clumped.

http://good-times.webshots.com/album/552314183KfaXmp

Happy Growing