Lenses + panohead to capture a full 360 image with 4 photographs

Hello everyone!

Thank you very much in advance for helping me.

I’ve got a Canon 5D and I’d like to purchase a lenses and a panoramic head to capture full 360 panoramas taking only 4 photographs. I don’t care very much about the nadir, but I really need to shoot only 4 images in total.

Which focal length should I use?

Can anyone recommend a good panoramic head?

Thanks!!!