"the finest gradation (a setting of 1) equates to a focus step equal to the lens focal length divided by 30. So with a 100mm lens, the smallest step would be a distance of 3.3mm, and the largest one 30mm. "
This may be inappropriately applied maths, but, approximately:
100mm FL lens,
Choose "1" = 3.3mm focus increments.
Assuming you want to be not diffraction limited, that's
Repro ratio 1:4 ie 0.25x
DOF (matching difraction blur) 3.5mm.
Field of view minimum 4 x (24 X 36) = 96 x 144mm.
Hand sized.. not bug sized.
Your subject can be 3 x 300 = 900 mm deep though, plus 20mm or so for the extra DoF at 900mm.
It would be more bug-friendly if it did 0.3mm focus steps, near 1:1.
Perhaps a firmware update may address that.
One obvious workaround would be to use coupled lenses ( a short one reversed on the front of the long one), but you may not get 45MP resolution.
If you create 24MP images, (ie less resolution) you can change to f/16 and get about half life size.
Could someone check the maths, please? I'd like to be wrong.