I left the back off, because I don't like it and indeed because it moved by warming up.
I set the camera to stacking and then he takes 15 photos and stacks them in the camera himself and then there is a 16th photo and I edit it a bit in photoshop.
I only use Helicon for focus bracketing.
Here's an explanation of how it works, and it's so nice and easy.
''Olympus offers two different focus bracketing modes – focus stacking and focus bracketing. Focus stacking is a capture of fifteen images at different focus depths stacked into one JPG within the camera. The original RAW images write to the memory card as well as the finished JPG stack. Focus Bracketing is a capture of up to 999 images at different focus depths and all RAW images write to the memory card for the photographer to stack using other stacking software (Helicon, PhotoShop, etc). This article discusses focus bracketing mode specifically. However, the focus stacking mode is almost identical.''