Alright, that helps explain it a lot!No problem. As a general rule, you want your part rated higher than your max expected voltage and current. Your voltage is a 9V battery which might go as high as 10V new, so 20V or higher adds some safety. The biggest current draw will be the LEDs. Currently, the max current draw on any one MOSFET comes from six LEDs wired in three sets of two. If we drive the LEDs at a max of 30mA, this works out to about 90mA pulled across the MOSFET. If we were to wire each LED individually, the draw would be 6 x 30mA = 180mA. So 500mA gives us plenty of room if we need it.
Ahh. nifty little things lol.Ah, that is why we are using the potentiometer. If you wanted to save some money and space, we could use the pot to determine what flash rate you want to stick with, measure the resistance across the pot, then replace it with a resistor. Since I assume you'll want to change the flash rate on the fly, I've added the pot. As long as it is in the circuit, you'll be able to change the flash rate on the fly. Now, I've used a square pot with a top adjustment. Since you want a low profile, you might want to use a rectangular pot with a side adjustment. In this way, you could put the pots both on one side or opposite sides of the board so the user can adjust either the red/blue or yellow/white flash rate whenever they want with a small screwdriver. Take a look at these: http://www.elexp.com/cmp_mtt1.htm.
At this point, im just compiling a shopping list. I'll probablt wait till i know everything that I need for sure before i order anything. Save on shipping, just ordering at 1 time. Plus I have a couple weeks before i get any LEDs anyway...Don't rush to buy the pots just yet - I want to test a few things and I might discover a wider range of adjustment by changing the pot value.