Electrical – Does the listed gauge on a crimp cap take into account that two wires would go in the same end

A 30A connection will require a much heavier wiring connection than either 12 AWG or 14 AWG. It is common that a 40A or 50A cord is used to hook up a range unit. These can be purchased in several lengths with molded on plugs at the end.

As always make sure that your outlet, wiring back to the entrance panel and the circuit breakers are sized properly for the load. The circuit components are normally rated a bit higher than the maximum current draw of the range. So a range unit that pulls 30 or 32A should be on a 40A circuit.

The maximum current for 1 AWG used in power transmission is 211 amps.(source) 70% of that is 147.7 amps.

2 AWG is rated at 94 amps, and 3 AWG is rated at 75 amps.

So there is no smaller wire rated at 70% or larger. You'll have to use 1 AWG (or larger) for all wires.

You could try an electrical supply house for other colors of 1 AWG, but I've found they only sell big spools (250+ feet) of such wire.

Try contacting a commercial electrician. They often carry those big spools around and might be willing to sell you a few feet of it. Of course they'll also want to charge you a $75 delivery fee and a $95 installation fee, but you should be able to avoid the first by going to them to pick it up, and the latter by firmly insisting that you don't want them to do it. Standard counter is they'll tell you it is illegal/dangerous/immoral for you to do it yourself. Stand your ground.