Putting book into a series

[Linda]

Please excuse me if this is the wrong location for this question. I will happily move it if necessary.

I have self-published three Kindle books at Amazon.com and I have a fourth ready to go. All are poetry except for one which is a mix of prose and poetry.

I am thinking of putting them into a series. Although they aren't like other series they are my complete collection of poetry to date.

I am also thinking of combining them into one print book.

I am also thinking of combining the four into one volume.

Is it best to change the covers of all four so they are similar or should I leave the single covers alone and just make the series covers similar?

Is this idea completely crazy?

What are your experiences with books in a series?

[Jerome]

For my fiction I have been setting up Omnibus (omniverse?) and Bundle books - each with a new cover - jerri

[Linda]

Jerome wrote: "For my fiction I have been setting up Omnibus (omniverse?) and Bundle books - each with a new cover - jerri"
How do you make your covers for your bundle (omnibus) books?

[Jerome]

I select from the Amazon catalog or menu of covers - I used to use images from Wikimedia - I used sexy art - vintage photos - Old Masters nudes etc - but decided to stay with Createspace art - jerri

[Linda]

Okay. Thanks!