I am thinking of switching to Mirrorless
With current thoughts being
Sony a7r3 / a73
Canon R/rp
Nikon z7/z6
Fuji gfx 50s/x-t3

Are any of these compatible?
Does using a rail add more precison than Helicon alone using lens stepper motor?
Canon eos rp has focus stacking, I imagine Helicon to have ...