Thanks Graymond!
There are more connections on RJ45 plugs so one can say control POV or other shift registers and stuff that need more pins. Plus my supplier runs low on RJ11 jacks but he will get RJ45 plugs at good price for kits. I'll be making RJ45 breakout boards and relay boards with RJ45 and terminal block connections.
I have to admit being a physicist doesn't improve my 3D intuition too much. We get things the easy way, like using dot product to find angle between two arbitrary lines in 3D, no need to think and feel. So I'm fond of mocking up my designs with paper or other stuff. My sensor block has the following combination:
GND-Volts-sig, and two other permutations minus their mirror images:) You're covered in all possible combination.