The Arca-Swiss tilt mechanism is axis tilt though not about the nodal point. While not optimal, it is a useful movement to gain a bit of foreground DOF, even with wide angle lenses. This movement may be reversed on the RM3di/RL3d & factum, to be used as swing, if desired. The rule of thumb is 1 mk on the adjustment wheel for every 30mm of focal length. However you should test to see best maximum for your lens. My 72mm is best at 2, my 43mm is best at 1 mk of tilt. As the other movements are in the rear, (rise/fall and lateral shift) point of view/perspective remain the same. The circle of confusion, COC, you mentioned is quite large for Digital. You really need .007 and even .005 for most precise DOF. .028 was the COC for 35mm film and as such many of the on line calculators are suspect. This was partially because film was thousandths thick while digital is only a micron thick.
We also have discovered that the lenses change character depending on the distance to the subject and the focal length. This means that the DOF charts are not completely linear from a short distance to infinity. This was probably always true, but wasn't discovered until the advent of precision tech cameras and the higher MP digital backs, which showed diffraction at larger apertures much sooner than film would. This means that F-11+ is almost unuseable with backs such as IQ180 & Leaf Credo 80 and Aptus 12. Around F8 being the best overall quality from these 80mp backs.
With film we often shot at F22 + with great results. This covered the focus shift encountered in all lenses, and as resolution wasn't what an 80mp backs can achieve, covered most errors.