I have some insight to these questions about diodes vs jumpers on G80, as I have finally gotten around to making an experiment. I took old G80-3000 ISO board I had with jumper, 2KRO. I installed the diodes.
I plugged it into the PC and BEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPP. Then it died. The controller is cooked I think. Now, I have a controller from an old G80-1000 that had NKRO, so I am going to see if I can install that into the 3000 and get it working again.
All Cherry cylindrical keycaps from G80/G81 have the same profile regardless of ABS, PBT or POM. Mix and match to however you like it. I have some photos of Cherry 2tone white/black, black/white, etc combos on my photobucket, but it is turned off for excessive traffic so I guess that won't really help you much.