calculating resistor size

I also wanted to mention that I don't necessarily need to get all of the brightness out of the LEDs. If I can run a different resistor and have them a little dimmer, that's fine too.

depends alot on the LED but i normally use 470. i use 1000 too but i also notice i can always use a 470 on the same resistor and its a little bit brighter.

Since both LED's have similar specs it makes it much easier. Use 2V as a reference for each LED. Assuming a nominal voltage of 12V from the battery, the voltage drop across the resistor should be 10V. Using Ohm's law, R=E/I. R = 10/0.024 = 417 ohms. The closest standard resistor is 430 ohms. With a nominal battery voltage of 14V, voltage drop across the resistor should be 12V, so R = 12/0.024 = 500 ohms and the closest standard resistor is 510 ohms. Depending how safe you want to be, you can a resistor is small as 430 ohms. A higher resistance would result in less brightness. If you decide to wire the LED's in parallel, you only need one resistor.