Just pulled a permit to do electrical on my new kitchen cabinets. Original wiring was the old cloth romex with no ground with some nasty problems that cropped up like 21 devices on a 15 amp circuit and on and on...

Dishwasher is on dedicated circuit with octogon box in back of cabinet. Do I wire from the box to dishwasher with BX or RX?

Garbage disposal will be wired on GFI circuit (2 duplexes and GFI with half horse disposal on 20 amp circuit on left circuit from sink) Should I use BX from octogon to disposal or leave as plastic romex.

I have seen both in the past and want to do it "right" the first time. Each side of the sink will be on its respective 20 amp breaker. All outlets and switches are rated 20 amps.