Question about dividing perennials

Question about dividing perennials

Hi! I'm looking for input regarding how best to divide my Goldstrum rudbeckia and when it should be done. I'm in Zone 5, SE Michigan. The plants are beginning to over-crowd the their bed. I am wondering, should I just cut back the foliage and divide them or wait till it dies back on its own? The weather is just starting to cool down here. I also want to be able to transfer the divisions to another area around the house. Thanks muchly in advance!!!
Porn!

Porn!

Dollar Store

Dollar Store

pesky pole, please help!

pesky pole, please help!

Some pictures of my garden

Some pictures of my garden

In the garden of weeden.

In the garden of weeden.

Please forgive my ignorance and many questions.

Please forgive my ignorance and many questions.