Experiment

As it was pouring with rain and horribly windy, I thought I'd have a go at taking a focus stacked macro shot indoors.  

As subject matter I selected a piece of wind blown moss, which I placed on a fallen branch and then set the camera up on the tripod using natural light from a window.

The resulting image is the combination of a focus stack of 99 separate exposures. 

What I learned from the process, is that if your macro lens focus breathes even a little bit, you are going to end up with problems when you try to combine the end results into a stack.  It is of course possible that dedicated focus stacking software such as Helicon or Zerene would do a better job than Affinity Photo. But I suspect that if you really want to do this sort of thing effectively one really does need a focus rail that allows you to move the camera and lens each time a shot is taken.  Of course, this only works with still subject matter, but if fungi, algae, lichen or slime moulds are your thing ...  I think I will be sticking with things that have wings for the time being :-)